@phdthesis{Ernst2006, author = {Ernst, Raffael}, title = {Anuran communities on the cutting edge : Analysing patterns and processes in anthropogenically altered tropical forests - Studies from the Guiana Shield and West Africa}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-18373}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2006}, abstract = {Summary Timber harvesting is currently the most common commercial utilisation activity in tropical forests. Assessing the effects of logging on different aspects of biodiversity and general ecosystem properties is hence of prime importance if the few remaining areas of intact tropical forest are to be protected effectively and efficiently. Tropical amphibian communities are an appropriate model system for studies on the impacts of human-induced environmental changes on the dynamics of complex biological systems. This thesis elaborates on patterns of diversity changes in tropical forest amphibian communities facing habitat alterations associated with selective logging in two globally important eco-regions (C{\^o}te d'Ivoire, Upper Guinea, West Africa and Guyana, the Guiana Shield, northern South America). The thesis is organised along two main themes. After a general introduction, a section on general methodology and an introduction to the model systems studied, the first theme moves from general patterns to underlying processes. A second theme running through both chapters carries from undisturbed systems to disturbed systems. A final section integrates findings and addresses implications for conservation management of anthropogenically altered tropical forests. Several case studies at the species- population and community level are being presented and data on the direct and indirect impacts of anthropogenic habitat alteration on respective organizational levels are provided. A key statement that is stressed on throughout the studies is the fact that common measures of diversity, such as species richness and species-diversity only inadequately reflect processes of diversity change following anthropogenic disturbance. They also fail to describe actual impacts on the dynamics of complex biological systems. It is argued that commonly used measures produce an incoherent and insufficient picture of diversity patterns and the underlying processes that shape these patterns. Thus, an understanding of higher levels of diversity, such as \&\#946;-diversity and functional diversity (and hence compositional patterns) appears to be the key to effectively mitigating the impacts of human-induced disturbance on amphibian communities. It is shown that the predictability of amphibian community composition depends on the respective level of anthropogenic disturbance imposed on a particular habitat. Hence, human activities that lead to changes in the structure of a forest, such as logging, not only alter simple system descriptors, such as the number of species in a given community, but rather alter the dynamics of the entire system. In this context, functional diversity is shown to be an important aspect underlying the actual mechanism that leads to the observed change of predictability patterns. Functional differences between species, rather than number of species per se appear to be the decisive factor in sustaining desirable ecosystem states and thus in maintaining important ecosystem services. Because biological diversity appears to play a substantial role in ecosystem resilience required to safeguard essential ecosystem functions in the face of environmental change, the thesis calls for a critical revision of common diversity assessments approaches. The studies advocate the reconsideration of the uncritical use of widespread measures and descriptors of biodiversity on grounds of inconsistent patterns found throughout numerous studies, including those presented herein.}, subject = {Tropischer Regenwald}, language = {en} } @article{ErbeldingDenkSchroderSchartletal.1994, author = {Erbelding-Denk, Claudia and Schroder, Johannes H. and Schartl, Manfred and Nanda, Indrajit and Schmid, Michael and Epplen, J{\"o}rg T.}, title = {Male polymorphism in Limia perugiae (Pisces: Poeciliidae)}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-61573}, year = {1994}, abstract = {The male-polymorphic poeciliid fish, Limia perugiae, a small teleostean endemic to the southeast of the Caribbean island Hispafiola, consists of three male size morphs with uniform females. Large males differentiate at a size va:rying between 25 and 38 mm; intermediate males, between 21 and 25 mm. Under competition, !arge males exhibit an elaborate courtship display, whereas small males show only a sneak-chase behavior. Intermediate males adapt their tactics to the respective competitors. However, all malemorphs can switch from courtship display to sneak-chase behavior. In large mating groups with four males of different size and five or six virgin females, large dominant a-males as weil as small subordinate \(\delta\)-males did not produce any offspring. Unexpectedly, all progeny were sired exclusively by the intemediate subordinate ß- and \(\gamma\)-males. Breeding experiments with the three male morphs can best be explained by a model of Y -linked genes for small and !arge size which are both suspended by the activity of an autosomal recessive repressor responsible for the development of intermediate males. The dominant allele of the recessive repressor, in either its homoorits heterozygous state, activates the Y-chromosomal genes for !arge or small size, respectively. Accordingly, intermediate males may produce male offspring of all size classes, depending on the presence of either the Y-linked gene or the autosomal repressor.}, subject = {Physiologische Chemie}, language = {en} } @incollection{EpplenAmmerEpplenetal.1991, author = {Epplen, J. T. and Ammer, H. and Epplen, C. and Kammerbauer, C. and Mitreiter, R. and Roewer, L. and Schwaiger, W. and Steimle, V. and Zischler, H. and Albert, E. and Andreas, A. and Beyermann, B. and Meyer, W. and Buitkamp, J. and Nanda, I. and N{\"u}rnberg, P. and Pena, S. D. J. and P{\"o}che, H. and Sprecher, W. and Schartl, Manfred and Weising, K. and Yassouridis, A.}, title = {Oligonucleotide fingerprinting using simple repeat motifs: a convenient, ubiquitously applicable method to detect hypervariability for multiple purposes}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-86371}, publisher = {Universit{\"a}t W{\"u}rzburg}, year = {1991}, abstract = {A panel of simple repetitive oligonucleotide probes has been designed and tested for multilocus DNA fingerprinting in some 200 fungal, plant and animal species as well as man. To date at least one of the probes has been found to be informative in each species. The human genome, however, has been the major target of many fingerprintins studies. Using the probe (CAC)5 or (GTG)5, individualization of all humans is possible except for monozygotic twins. Paternity analyses are now perfonned on a routine basis by the use of multilocus fingerprints, inctuding also cases of deficiency, i.e. where one of the parents is not available for analysis. In forensie science stain analysis is feasible in all tissue remains containing nuc)eated cells. Depending on the degree of DNA degradation a variety of oligonucleotides are informative, and they have been proven useful in actual case work. Advantages in comparison to other methods including enzymatic DNA amplification techniques (PCR) are evident. Fingerprint patterns of tumors may be changed due to the gain or loss of chromosomes and/or intrachromosomal deletion and amplification events. Locus-specific probes were isolated from the human (CAC)5/( GTG)5 fingerprint with a varying degree of informativeness (monomorphic versus truly hypervariable markers). The feasibility of three different approaches. for the isolation of hypervariable mono-locus probes was evaluated. Finally, one particular mixed simple (gt)n(ga)m repeat locus in the second intron of the HLA-DRB genes has been scrutinized to allow comparison of the extent of exon-encoded (protein-) polymorphisms versus intronie bypervariability of simple repeats: adjacent to a single gene sequence (e.g. HLA-DRB1*0401) many different length alleles were found. Group-specific structures of basic repeats were identified within the evolutionarily related DRB alleles. As a further application it is suggested here that due to the ubiquitous interspersion of their targets, short probes for simple repeat sequences are especially useful tools for ordering genomic cosmid, yeast artificial chromosome and phage banks.}, subject = {DNS}, language = {en} } @article{EngstlerBeneke2023, author = {Engstler, Markus and Beneke, Tom}, title = {Gene editing and scalable functional genomic screening in Leishmania species using the CRISPR/Cas9 cytosine base editor toolbox LeishBASEedit}, series = {eLife}, volume = {12}, journal = {eLife}, doi = {10.7554/eLife.85605}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-350002}, year = {2023}, abstract = {CRISPR/Cas9 gene editing has revolutionised loss-of-function experiments in Leishmania, the causative agent of leishmaniasis. As Leishmania lack a functional non-homologous DNA end joining pathway however, obtaining null mutants typically requires additional donor DNA, selection of drug resistance-associated edits or time-consuming isolation of clones. Genome-wide loss-of-function screens across different conditions and across multiple Leishmania species are therefore unfeasible at present. Here, we report a CRISPR/Cas9 cytosine base editor (CBE) toolbox that overcomes these limitations. We employed CBEs in Leishmania to introduce STOP codons by converting cytosine into thymine and created http://www.leishbaseedit.net/ for CBE primer design in kinetoplastids. Through reporter assays and by targeting single- and multi-copy genes in L. mexicana, L. major, L. donovani, and L. infantum, we demonstrate how this tool can efficiently generate functional null mutants by expressing just one single-guide RNA, reaching up to 100\% editing rate in non-clonal populations. We then generated a Leishmania-optimised CBE and successfully targeted an essential gene in a plasmid library delivered loss-of-function screen in L. mexicana. Since our method does not require DNA double-strand breaks, homologous recombination, donor DNA, or isolation of clones, we believe that this enables for the first time functional genetic screens in Leishmania via delivery of plasmid libraries.}, language = {en} } @article{EnglmeiervonHoermannRiekeretal.2022, author = {Englmeier, Jana and von Hoermann, Christian and Rieker, Daniel and Benbow, Marc Eric and Benjamin, Caryl and Fricke, Ute and Ganuza, Cristina and Haensel, Maria and Lackner, Tom{\´a}š and Mitesser, Oliver and Redlich, Sarah and Riebl, Rebekka and Rojas-Botero, Sandra and Rummler, Thomas and Salamon, J{\"o}rg-Alfred and Sommer, David and Steffan-Dewenter, Ingolf and Tobisch, Cynthia and Uhler, Johannes and Uphus, Lars and Zhang, Jie and M{\"u}ller, J{\"o}rg}, title = {Dung-visiting beetle diversity is mainly affected by land use, while community specialization is driven by climate}, series = {Ecology and Evolution}, volume = {12}, journal = {Ecology and Evolution}, number = {10}, issn = {2045-7758}, doi = {10.1002/ece3.9386}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-312846}, year = {2022}, abstract = {Dung beetles are important actors in the self-regulation of ecosystems by driving nutrient cycling, bioturbation, and pest suppression. Urbanization and the sprawl of agricultural areas, however, destroy natural habitats and may threaten dung beetle diversity. In addition, climate change may cause shifts in geographical distribution and community composition. We used a space-for-time approach to test the effects of land use and climate on α-diversity, local community specialization (H\(_2\)′) on dung resources, and γ-diversity of dung-visiting beetles. For this, we used pitfall traps baited with four different dung types at 115 study sites, distributed over a spatial extent of 300 km × 300 km and 1000 m in elevation. Study sites were established in four local land-use types: forests, grasslands, arable sites, and settlements, embedded in near-natural, agricultural, or urban landscapes. Our results show that abundance and species density of dung-visiting beetles were negatively affected by agricultural land use at both spatial scales, whereas γ-diversity at the local scale was negatively affected by settlements and on a landscape scale equally by agricultural and urban land use. Increasing precipitation diminished dung-visiting beetle abundance, and higher temperatures reduced community specialization on dung types and γ-diversity. These results indicate that intensive land use and high temperatures may cause a loss in dung-visiting beetle diversity and alter community networks. A decrease in dung-visiting beetle diversity may disturb decomposition processes at both local and landscape scales and alter ecosystem functioning, which may lead to drastic ecological and economic damage.}, language = {en} } @article{EnglmeierMitesserBenbowetal.2023, author = {Englmeier, Jana and Mitesser, Oliver and Benbow, M. Eric and Hothorn, Torsten and von Hoermann, Christian and Benjamin, Caryl and Fricke, Ute and Ganuza, Cristina and Haensel, Maria and Redlich, Sarah and Riebl, Rebekka and Rojas Botero, Sandra and Rummler, Thomas and Steffan-Dewenter, Ingolf and Stengel, Elisa and Tobisch, Cynthia and Uhler, Johannes and Uphus, Lars and Zhang, Jie and M{\"u}ller, J{\"o}rg}, title = {Diverse effects of climate, land use, and insects on dung and carrion decomposition}, series = {Ecosystems}, volume = {26}, journal = {Ecosystems}, number = {2}, issn = {1432-9840}, doi = {10.1007/s10021-022-00764-7}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-325064}, pages = {397-411}, year = {2023}, abstract = {Land-use intensification and climate change threaten ecosystem functions. A fundamental, yet often overlooked, function is decomposition of necromass. The direct and indirect anthropogenic effects on decomposition, however, are poorly understood. We measured decomposition of two contrasting types of necromass, rat carrion and bison dung, on 179 study sites in Central Europe across an elevational climate gradient of 168-1122 m a.s.l. and within both local and regional land uses. Local land-use types included forest, grassland, arable fields, and settlements and were embedded in three regional land-use types (near-natural, agricultural, and urban). The effects of insects on decomposition were quantified by experimental exclusion, while controlling for removal by vertebrates. We used generalized additive mixed models to evaluate dung weight loss and carrion decay rate along elevation and across regional and local land-use types. We observed a unimodal relationship of dung decomposition with elevation, where greatest weight loss occurred between 600 and 700 m, but no effects of local temperature, land use, or insects. In contrast to dung, carrion decomposition was continuously faster with both increasing elevation and local temperature. Carrion reached the final decomposition stage six days earlier when insect access was allowed, and this did not depend on land-use effect. Our experiment identified different major drivers of decomposition on each necromass form. The results show that dung and carrion decomposition are rather robust to local and regional land use, but future climate change and decline of insects could alter decomposition processes and the self-regulation of ecosystems.}, language = {en} } @phdthesis{Englmeier2024, author = {Englmeier, Jana}, title = {Consequences of climate change and land-use intensification for decomposer communities and decomposition processes}, doi = {10.25972/OPUS-31399}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-313994}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2024}, abstract = {The increase in intensively used areas and climate change are direct and indirect consequences of anthropogenic actions, caused by a growing population and increasing greenhouse gas emissions. The number of research studies, investigating the effects of land use and climate change on ecosystems, including flora, fauna, and ecosystem services, is steadily growing. This thesis contributes to this research area by investigating land-use and climate effects on decomposer communities (arthropods and microbes) and the ecosystem service 'decomposition of dead material'. Chapter II deals with consequences of intensified land use and climate change for the ecosystem service 'decomposition of dead organic material' (necromass). Considering the severe decline in insects, we experimentally excluded insects from half of the study objects. The decomposition of both dung and carrion was robust to land-use changes. Dung decomposition, moreover, was unaffected by temperature and the presence/ absence of insects. Along the altitudinal gradient, however, highest dung decomposition was observed at medium elevation between 600 and 700 m above sea level (although insignificant). As a consequence, we assume that at this elevation there is an ideal precipitation:temperature ratio for decomposing organisms, such as earthworms or collembolans. Carrion decomposition was accelerated by increasing elevation and by the presence of insects, indicating that increasing variability in climate and an ongoing decline in insects could modify decomposition processes and consequently natural nutrient cycles. Moreover, we show that different types of dead organic material respond differently to environmental factors and should be treated separately in future studies. In Chapter III, we investigated land-use and climate effects on dung-visiting beetles and their resource specialization. Here, all beetles that are preferentially found on dung, carrion or other rotten material were included. Both α- and γ-diversity were strongly reduced in agricultural and urban areas. High precipitation reduced dung-visiting beetle abundance, whereas γ-diversity was lowest in the warmest regions. Resource specialization decreased with increasing temperatures. The results give evidence that land use as well as climate can alter dung-visiting beetle diversity and resource specialization and may hence influence the natural balance of beetle communities and their contribution to the ecosystem service 'decomposition of dead material'. The following chapter, Chapter IV, contributes to the findings in Chapter II. Here, carrion decomposition is not only explained by land-use intensity and climate but also by diversity and community composition of two taxonomic groups found on carrion, beetles and bacteria. The results revealed a strong correlation between bacteria diversity and community composition with temperature. Carrion decomposition was to a great extent directed by bacterial community composition and precipitation. The role of beetles was neglectable in carrion decomposition. With this study, I show that microbes, despite their microscopic size, direct carrion decomposition and may not be neglected in future decomposition studies. In Chapter V a third necromass type is investigated, namely deadwood. The aim was to assess climate and land-use effects on deadwood-inhabiting fungi and bacteria. Main driver for microbial richness (measured as number of OTUs) was climate, including temperature and precipitation. Warmer climates promoted the diversity of bacteria, whereas fungi richness was unaffected by temperature. In turn, fungi richness was lower in urban landscapes compared to near-natural landscapes and bacteria richness was higher on meadows than on forest sites. Fungi were extremely specialized on their host tree, independent of land use and climate. Bacteria specialization, however, was strongly directed by land use and climate. These results underpin previous studies showing that fungi are highly specialized in contrast to bacteria and add new insights into the robustness of fungi specialization to climate and land use. I summarize that climate as well as intensive land use influence biodiversity. Temperature and precipitation, however, had positive and negative effects on decomposer diversity, while anthropogenic land use had mostly negative effects on the diversity of decomposers.}, subject = {Mikroorganismus}, language = {en} } @phdthesis{Englberger2012, author = {Englberger, Eva}, title = {Gene regulation in hearts of Hey-mutant mouse embryos and monitoring of sub-cellular Hey1 distribution}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-73395}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2012}, abstract = {Hey-mutant mouse hearts at embryonic day E14.5 were shown to react to the knock out of Hey2 with several up-regualted genes. This up-regulation is due to the lack of Hey2 and cannot be explained by the structural changes in heart morphology as shown using control animals. Part of the gene regulation was further validated using in situ hybridization. Hey1 was located to the nucleus in immunofluorescence experiments. However, experiments on protein level showed also amount of Hey1 within the cytoplasm. The nuclear localization of Hey1 was unchanged during all cell cycle phases as well as when CaMKII was co-expressed or other cellular pathways were inhibited or stimulated. Hey1 does not seem to interact with the nuclear transport proteins importin-alpha and -beta, therefore it still needs to be elucidated how Hey1 is transported into the nucleus.}, subject = {Maus}, language = {en} } @phdthesis{Engelmann2008, author = {Engelmann, Julia Cath{\´e}rine}, title = {DNA microarrays: applications and novel approaches for analysis and interpretation}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-29747}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2008}, abstract = {In der vorliegenden Dissertation wird die Entwicklung eines phylogenetischen DNA Microarrays, die Analyse von mehreren Microarray-Genexpressionsdatens{\"a}tzen und neue Ans{\"a}tze f{\"u}r die Datenanalyse und Interpretation der Ergebnisse vorgestellt. Die Entwicklung und Analyse der Daten eines phylogenetischen DNA Microarrays wird in der ersten Publikation dargestellt. Ich konnte zeigen, dass die Spezies-Detektion mit phylogenetischen Microarrays durch die Datenanalyse mit einem linearen Regressionsansatz signifikant verbessert werden kann. Standard-Methoden haben bislang nur Signalintensit{\"a}ten betrachtet und eine Spezies als an- oder abwesend bezeichnet, wenn die Signalintensit{\"a}t ihres Messpunktes oberhalb eines willk{\"u}rlich gesetzten Schwellenwertes lag. Dieses Verfahren ist allerdings aufgrund von Kreuz-Hybridisierungen nicht auf sehr nah verwandte Spezies mit hoher Sequenzidentit{\"a}t anwendbar. Durch die Modellierung des Hybridisierungs und Kreuz-Hybridisierungsverhaltens mit einem linearen Regressionsmodell konnte ich zeigen, dass Spezies mit einer Sequenz{\"a}hnlichkeit von 97\% im Markergen immer noch unterschieden werden k{\"o}nnen. Ein weiterer Vorteil der Modellierung ist, dass auch Mischungen verschiedener Spezies zuverl{\"a}ssig vorhergesagt werden k{\"o}nnen. Theoretisch sind auch quantitative Vorhersagen mit diesem Modell m{\"o}glich. Um die großen Datenmengen, die in {\"o}ffentlichen Microarray-Datenbanken abgelegt sind besser nutzen zu k{\"o}nnen, bieten sich Meta-Analysen an. In der zweiten Publikation wird eine explorative Meta-Analyse auf Arabidopsis thaliana-Datens{\"a}tzen vorgestellt. Mit der Analyse verschiedener Datens{\"a}tze, die den Einfluss von Pflanzenhormonen, Pathogenen oder verschiedenen Mutationen auf die Genexpression untersucht haben, konnten die Datens{\"a}tze anhand ihrer Genexpressionsprofile in drei große Gruppen eingeordnet werden: Experimente mit Indol-3-Essigs{\"a}ure (IAA), mit Pathogenen und andere Experimente. Gene, die charakteristisch f{\"u}r die Gruppe der IAA-Datens{\"a}tze beziehungsweise f{\"u}r die Gruppe der Pathogen-Datens{\"a}tze sind, wurden n{\"a}her betrachtet. Diese Gene hatten Funktionen, die bereits mit Pathogenbefall bzw. dem Einfluss von IAA in Verbindung gebracht wurden. Außerdem wurden Hypothesen {\"u}ber die Funktionen von bislang nicht annotierten Genen aufgestellt. In dieser Arbeit werden auch Prim{\"a}ranalysen von einzelnen Arabidopsis thaliana Genexpressions-Datens{\"a}tzen vorgestellt. In der dritten Publikation wird ein Experiment beschrieben, das durchgef{\"u}hrt wurde um herauszufinden ob Mikrowellen-Strahlung einen Einfluss auf die Genexpression einer Zellkultur hat. Dazu wurden explorative Analysemethoden angewendet. Es wurden geringe aber signifikante Ver{\"a}nderungen in einer sehr kleinen Anzahl von Genen beobachtet, die experimentell best{\"a}tigt werden konnten. Die Funktionen der regulierten Gene und eine Meta-Analyse mit {\"o}ffentlich zug{\"a}nglichen Datens{\"a}tzen einer Datenbank deuten darauf hin, dass die pflanzliche Zellkultur die Strahlung als eine Art Energiequelle {\"a}hnlich dem Licht wahrnimmt. Des weiteren wird in der vierten Publikation die funktionelle Analyse eines Arabidopsis thaliana Genexpressionsdatensatzes beschrieben. Die Analyse der Genexpressions eines pflanzlichen Tumores zeigte, dass er seinen Stoffwechsel von aerob und auxotroph auf anaerob und heterotroph umstellt. Gene der Photosynthese werden im Tumorgewebe reprimiert, Gene des Aminos{\"a}ure- und Fettstoffwechsels, der Zellwand und Transportkan{\"a}le werden so reguliert, dass Wachstum und Entwicklung des Tumors gef{\"o}rdert werden. In der f{\"u}nften Publikation in dieser Arbeit wird GEPAT (Genome Expression Pathway Analysis Tool) beschrieben. Es besteht aus einer Internet- Anwendung und einer Datenbank, die das einfache Hochladen von Datens{\"a}tzen in die Datenbank und viele M{\"o}glichkeiten der Datenanalyse und die Integration anderer Datentypen erlaubt. In den folgenden zwei Publikationen (Publikation 6 und Publikation 7) wird GEPAT auf humane Microarray-Datens{\"a}tze angewendet um Genexpressionsdaten mit weiteren Datentypen zu verkn{\"u}pfen. Genexpressionsdaten und Daten aus vergleichender Genom-Hybridisierung (CGH) von prim{\"a}ren Tumoren von 71 Mantel-Zell-Lymphom (MCL) Patienten erm{\"o}glichte die Ermittlung eines Pr{\"a}diktors, der die Vorhersage der {\"U}berlebensdauer von Patienten gegen{\"u}ber herk{\"o}mmlichen Methoden verbessert. Die Analyse der CGH Daten zeigte, dass auch diese f{\"u}r die Vorhersage der {\"U}berlebensdauer geeignet sind. F{\"u}r den Datensatz von Patienten mit großzellig diffusem B-Zell-Lymphom DLBCL konnte aus den Genexpressionsdaten ebenfalls ein neuer Pr{\"a}diktor vorgeschlagen werden. Mit den zwischen lang und kurz {\"u}berlebenden Patienten differentiell exprimierten Genen der MCL Patienten und mit den Genen, die zwischen den beiden Untergruppen von DLBCL reguliert sind, wurden Interaktionsnetzwerke gebildet. Diese zeigen, dass bei beiden Krebstypen Gene des Zellzyklus und der Proliferation zwischen Patienten mit kurzer und langer {\"U}berlebensdauer unterschiedlich reguliert sind.}, subject = {Microarray}, language = {en} } @phdthesis{EngelhardtgebChristiansen2013, author = {Engelhardt [geb. Christiansen], Frauke}, title = {Synaptic Connectivity in the Mushroom Body Calyx of Drosophila melanogaster}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-85058}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2013}, abstract = {Learning and memory is considered to require synaptic plasticity at presynaptic specializations of neurons. Kenyon cells are the intrinsic neurons of the primary olfactory learning center in the brain of arthropods - the mushroom body neuropils. An olfactory mushroom body memory trace is supposed to be located at the presynapses of Kenyon cells. In the calyx, a sub-compartment of the mushroom bodies, Kenyon cell dendrites receive olfactory input provided via projection neurons. Their output synapses, however, were thought to reside exclusively along their axonal projections outside the calyx, in the mushroom body lobes. By means of high-resolution imaging and with novel transgenic tools, we showed that the calyx of the fruit fly Drosophila melanogaster also comprised Kenyon cell presynapses. At these presynapses, synaptic vesicles were present, which were capable of neurotransmitter release upon stimulation. In addition, the newly identified Kenyon cell presynapses shared similarities with most other presynapses: their active zones, the sites of vesicle fusion, contained the proteins Bruchpilot and Syd-1. These proteins are part of the cytomatrix at the active zone, a scaffold controlling synaptic vesicle endo- and exocytosis. Kenyon cell presynapses were present in γ- and α/β-type KCs but not in α/β-type Kenyon cells. The newly identified Kenyon cell derived presynapses in the calyx are candidate sites for an olfactory associative memory trace. We hypothesize that, as in mammals, recurrent neuronal activity might operate for memory retrieval in the fly olfactory system. Moreover, we present evidence for structural synaptic plasticity in the mushroom body calyx. This is the first demonstration of synaptic plasticity in the central nervous system of Drosophila melanogaster. The volume of the mushroom body calyx can change according to changes in the environment. Also size and numbers of microglomeruli - sub-structures of the calyx, at which projection neurons contact Kenyon cells - can change. We investigated the synapses within the microglomeruli in detail by using new transgenic tools for visualizing presynaptic active zones and postsynaptic densities. Here, we could show, by disruption of the projection neuron - Kenyon cell circuit, that synapses of microglomeruli were subject to activity-dependent synaptic plasticity. Projection neurons that could not generate action potentials compensated their functional limitation by increasing the number of active zones per microglomerulus. Moreover, they built more and enlarged microglomeruli. Our data provide clear evidence for an activity-induced, structural synaptic plasticity as well as for the activity-induced reorganization of the olfactory circuitry in the mushroom body calyx.}, subject = {Taufliege}, language = {en} } @article{EndresKneitzOrthetal.2016, author = {Endres, Marcel and Kneitz, Susanne and Orth, Martin F. and Perera, Ruwan K. and Zernecke, Alma and Butt, Elke}, title = {Regulation of matrix metalloproteinases (MMPs) expression and secretion in MDA-MB-231 breast cancer cells by LIM and SH3 protein 1 (LASP1)}, series = {Oncotarget}, volume = {7}, journal = {Oncotarget}, number = {39}, doi = {10.18632/oncotarget.11720}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-176920}, pages = {64244-64259}, year = {2016}, abstract = {The process of tumor invasion requires degradation of extracellular matrix by proteolytic enzymes. Cancer cells form protrusive invadopodia, which produce and release matrix metalloproteinases (MMPs) to degrade the basement membrane thereby enabling metastasis. We investigated the effect of LASP1, a newly identified protein in invadopodia, on expression, secretion and activation of MMPs in invasive breast tumor cell lines. By analyzing microarray data of in-house generated control and LASP1-depleted MDA-MB-231 breast cancer cells, we observed downregulation of MMP1, -3 and -9 upon LASP1 depletion. This was confirmed by Western blot analysis. Conversely, rescue experiments restored in part MMP expression and secretion. The regulatory effect of LASP1 on MMP expression was also observed in BT-20 breast cancer cells as well as in prostate and bladder cancer cell lines. In line with bioinformatic FunRich analysis of our data, which mapped a high regulation of transcription factors by LASP1, public microarray data analysis detected a correlation between high LASP1 expression and enhanced c-Fos levels, a protein that is part of the transcription factor AP-1 and known to regulate MMP expression. Compatibly, in luciferase reporter assays, AP-1 showed a decreased transcriptional activity after LASP1 knockdown. Zymography assays and Western blot analysis revealed an additional promotion of MMP secretion into the extracellular matrix by LASP1, thus, most likely, altering the microenvironment during cancer progression. The newly identified role of LASP1 in regulating matrix degradation by affecting MMP transcription and secretion elucidated the migratory potential of LASP1 overexpressing aggressive tumor cells in earlier studies.}, language = {en} } @article{EndresJungblutDivyapicigiletal.2022, author = {Endres, Leo M. and Jungblut, Marvin and Divyapicigil, Mustafa and Sauer, Markus and Stigloher, Christian and Christodoulides, Myron and Kim, Brandon J. and Schubert-Unkmeir, Alexandra}, title = {Development of a multicellular in vitro model of the meningeal blood-CSF barrier to study Neisseria meningitidis infection}, series = {Fluids and Barriers of the CNS}, volume = {19}, journal = {Fluids and Barriers of the CNS}, number = {1}, doi = {10.1186/s12987-022-00379-z}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-300208}, year = {2022}, abstract = {Background Bacterial meningitis is a life-threatening disease that occurs when pathogens such as Neisseria meningitidis cross the meningeal blood cerebrospinal fluid barrier (mBCSFB) and infect the meninges. Due to the human-specific nature of N. meningitidis, previous research investigating this complex host-pathogen interaction has mostly been done in vitro using immortalized brain endothelial cells (BECs) alone, which often do not retain relevant barrier properties in culture. Here, we developed physiologically relevant mBCSFB models using BECs in co-culture with leptomeningeal cells (LMCs) to examine N. meningitidis interaction. Methods We used BEC-like cells derived from induced pluripotent stem cells (iBECs) or hCMEC/D3 cells in co-culture with LMCs derived from tumor biopsies. We employed TEM and structured illumination microscopy to characterize the models as well as bacterial interaction. We measured TEER and sodium fluorescein (NaF) permeability to determine barrier tightness and integrity. We then analyzed bacterial adherence and penetration of the cell barrier and examined changes in host gene expression of tight junctions as well as chemokines and cytokines in response to infection. Results Both cell types remained distinct in co-culture and iBECs showed characteristic expression of BEC markers including tight junction proteins and endothelial markers. iBEC barrier function as determined by TEER and NaF permeability was improved by LMC co-culture and remained stable for seven days. BEC response to N. meningitidis infection was not affected by LMC co-culture. We detected considerable amounts of BEC-adherent meningococci and a relatively small number of intracellular bacteria. Interestingly, we discovered bacteria traversing the BEC-LMC barrier within the first 24 h post-infection, when barrier integrity was still high, suggesting a transcellular route for N. meningitidis into the CNS. Finally, we observed deterioration of barrier properties including loss of TEER and reduced expression of cell-junction components at late time points of infection. Conclusions Here, we report, for the first time, on co-culture of human iPSC derived BECs or hCMEC/D3 with meningioma derived LMCs and find that LMC co-culture improves barrier properties of iBECs. These novel models allow for a better understanding of N. meningitidis interaction at the mBCSFB in a physiologically relevant setting.}, language = {en} } @phdthesis{Endler2006, author = {Endler, Annett}, title = {Regulation of reproductive division of labor in the ant Camponotus floridanus : behavioral mechanisms and pheromonal effects}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-18872}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2006}, abstract = {A hitherto unresolved problem is how workers are prevented from reproducing in large insect societies. The queen informs about her fertility and health which ensures sufficient indirect fitness benefits for workers. In the ant Camponotus floridanus, I found such a signal located on eggs of highly fertile queens. Groups of workers were regularly provided with different sets of brood. Only in groups with queen eggs workers refrain from reproducing. Thus, the eggs seem to inform the workers about queen presence. The signal on queen eggs is presumably the same that enables workers to distinguish between queen and worker-laid eggs, latter are destroyed by workers. Queen and worker-laid eggs differ in their surface hydrocarbons in a similar way as fertile queens differ from workers in the composition of their cuticular hydrocarbons. When I transferred hydrocarbons from the queen cuticle to worker eggs the eggs were no longer destroyed, indicating that they now carry the signal. These hydrocarbons thus represent a queen signal that regulates worker reproduction in this species. But the signal is not present in all fertile queens. Founding queens with low egg-laying rates differ in the composition of cuticular hydrocarbons from queens with high productivity. Similar differences in the composition of surface hydrocarbons were present on their eggs. The queen signal develops along with an increasing fertility and age of the queen, and this is perceived by the workers. Eggs from founding queens were destroyed like worker eggs. This result shows that founding queens lack the appropriate signal. In these little colony foundations chemical communication of queen status may not be necessary to prevent workers from reproducing, since workers may benefit more from investing in colony growth and increased productivity of large colonies rather than from producing male eggs in incipient colonies. If the queen is missing or the productivity of the queen decreases, workers start laying eggs. There is some evidence from correlative studies that, under queenless conditions, worker police each other because of differences in individual odors as a sign of social status. It can be expressed as either aggressive inhibition of ovarian activity, workers with developed ovaries are attacked by nest-mates, or destruction by worker-laid eggs. I found that in C. floridanus workers, in contrast to known studies, police only by egg eating since they are able to discriminate queen- and worker-laid eggs. Workers with developed ovaries will never attacked by nest-mates. This is further supported by qualitative and quantitative differences in the cuticular hydrocarbon profile of queens and workers, whereas profiles of workers with and without developed ovaries show a high similarity. I conclude that workers discriminate worker eggs on the basis of their hydrocarbon profile, but they are not able to recognize egg-laying nest-mates. Improving our knowledge of the proximate mechanisms of the reproductive division of labor in evolutionary derived species like C. floridanus will help to understand the evolution of extreme reproductive altruism involving sterility as a characteristic feature of advanced eusocial systems.}, subject = {Camponotus floridanus}, language = {en} } @article{EndesfelderMalkuschFlottmannetal.2011, author = {Endesfelder, Ulrike and Malkusch, Sebastian and Flottmann, Benjamin and Mondry, Justine and Liguzinski, Piotr and Verveer, Peter J. and Heilemann, Mike}, title = {Chemically Induced Photoswitching of Fluorescent Probes - A General Concept for Super-Resolution Microscopy}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-74896}, year = {2011}, abstract = {We review fluorescent probes that can be photoswitched or photoactivated and are suited for single-molecule localization based super-resolution microscopy. We exploit the underlying photochemical mechanisms that allow photoswitching of many synthetic organic fluorophores in the presence of reducing agents, and study the impact of these on the photoswitching properties of various photoactivatable or photoconvertible fluorescent proteins. We have identified mEos2 as a fluorescent protein that exhibits reversible photoswitching under various imaging buffer conditions and present strategies to characterize reversible photoswitching. Finally, we discuss opportunities to combine fluorescent proteins with organic fluorophores for dual-color photoswitching microscopy.}, subject = {Super-Resolution Microscopy}, language = {en} } @article{EndesfelderMalkuschFlottmannetal.2011, author = {Endesfelder, Ulrike and Malkusch, Sebastian and Flottmann, Benjamin and Mondry, Justine and Liguzinski, Piotr and Verveer, Peter J. and Heilemann, Mike}, title = {Chemically Induced Photoswitching of Fluorescent Probes - A General Concept for Super-Resolution Microscopy}, series = {Molecules}, volume = {16}, journal = {Molecules}, number = {4}, doi = {10.3390/molecules16043106}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-134080}, pages = {3106-3118}, year = {2011}, abstract = {We review fluorescent probes that can be photoswitched or photoactivated and are suited for single-molecule localization based super-resolution microscopy. We exploit the underlying photochemical mechanisms that allow photoswitching of many synthetic organic fluorophores in the presence of reducing agents, and study the impact of these on the photoswitching properties of various photoactivatable or photoconvertible fluorescent proteins. We have identified mEos2 as a fluorescent protein that exhibits reversible photoswitching under various imaging buffer conditions and present strategies to characterize reversible photoswitching. Finally, we discuss opportunities to combine fluorescent proteins with organic fluorophores for dual-color photoswitching microscopy.}, language = {en} } @phdthesis{Eltz2001, author = {Eltz, Thomas}, title = {Ecology of stingless bees (Apidae, Meliponini) in lowland dipterocarp forests in Sabah, Malaysia, and an evaluation of logging impact on populations and communities}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-1130}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2001}, abstract = {The present thesis reports on four years of field research on stingless bee ecology in Sabah, Malaysia. Hereby, it was the main focus to evaluate the effect of selective logging for timber extraction on communities of bees, and to elucidate causative relationships involved in regulating bee populations. Included were background studies on resource use (3.1, 3.2, 3.3) and nesting biology (3.4) as well as comparative studies on stingless bee diversity and abundance in logged and unlogged lowland rainforest sites (4.1, 4.2). Stingless bees proved to be generalist foragers that used a large range of plant species as pollen sources. Nevertheless, different species of bees had rather distinct pollen diets, a findind that was independent of fluctuations in flowering activity in the habitat. At one particular point in time colonies of one species (Trigona collina)collected mold spores (Rhizopus sp.) as a pollen surrogate. In order to obtain low-effort estimates of meliponine pollen sources a new method was developed: Trapping of bee garbage (with funnel traps) and the quantitative analysis of pollen in garbage samples. Pollen in bee garbage reflected pollen import with a certain time lag and could therefore be used for an assessment of long-term pollen foraging (see below). The majority of stingless bee nests (275 nests of 12 species) were found in cavities in trunks or under the bases of large, living canopy trees. Nest trees mostly belonged to commercial species and were of the correct size and (partly) timber quality to warrant harvesting. It was estimated that roughly one third of stingless bee nests in an given forest area would be killed during a selective logging operation. Besides causing direct mortality, logging may also indirectly affect bee populations by reducing the availability of potential nest sites (trees). However, in a comparison of primary and differentially logged forest sites (10 to 30 years after logging) no effect of the degree of disturbance on meliponine nest density was found. Instead, the variation in nest density (0 to 16.2 nest/ha) was best explained by differences in the available floral resources (assessed by analysis of pollen in bee garbage). Bee populations in forest edge situations were favored: there was a positive correlation between nest density and the proportion of external non-forest pollen (e.g. from crop plants, road edge vegetation, mangroves) in the bees' diet. The highest nest density was found in a site bordering the mangroves in Sandakan Bay. Here, the mangrove tree Rhizophora apiculata represented a extraordinary large fraction of the pollen volume. Presumably, external pollen sources effectively supplement bee diets at times when little flowering occurs inside the forest, thus increasing overall bee carrying-capacity. The idea of differential pollen limitation was strengthened by direct measurements of pollen import and foraging activity over a period of five months. Both were elevated in colonies in a site with high bee density. It is concluded that the abundance of stingless bees in forests in Sabah is chiefly dependent on the local availability of food resources. Hereby, bee populations strongly benefit from edge effects and increased habitat diversity. Although direct negative effects of selective logging are strongly indicated by a close association of bee nests with commercial trees, no clear effects were detected in regenerating forests ten to 30 years after logging.}, subject = {Sabah}, language = {en} } @article{ElkonLoayzaPuchKorkmazetal.2015, author = {Elkon, Ran and Loayza-Puch, Fabricio and Korkmaz, Gozde and Lopes, Rui and van Breugel, Pieter C and Bleijerveld, Onno B and Altelaar, AF Maarten and Wolf, Elmar and Lorenzin, Francesca and Eilers, Martin and Agami, Reuven}, title = {Myc coordinates transcription and translation to enhance transformation and suppress invasiveness}, series = {EMBO reports}, volume = {16}, journal = {EMBO reports}, number = {12}, doi = {10.15252/embr.201540717}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-150373}, pages = {1723-1736}, year = {2015}, abstract = {c-Myc is one of the major human proto-oncogenes and is often associated with tumor aggression and poor clinical outcome. Paradoxically, Myc was also reported as a suppressor of cell motility, invasiveness, and metastasis. Among the direct targets of Myc are many components of the protein synthesis machinery whose induction results in an overall increase in protein synthesis that empowers tumor cell growth. At present, it is largely unknown whether beyond the global enhancement of protein synthesis, Myc activation results in translation modulation of specific genes. Here, we measured Myc-induced global changes in gene expression at the transcription, translation, and protein levels and uncovered extensive transcript-specific regulation of protein translation. Particularly, we detected a broad coordination between regulation of transcription and translation upon modulation of Myc activity and showed the connection of these responses to mTOR signaling to enhance oncogenic transformation and to the TGFβ pathway to modulate cell migration and invasiveness. Our results elucidate novel facets of Myc-induced cellular responses and provide a more comprehensive view of the consequences of its activation in cancer cells.}, language = {en} } @phdthesis{ElMasri2005, author = {El-Masri, Harun}, title = {A genetic analysis of somitogenesis in the Medaka (Oryzias latipes)}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-14515}, school = {Universit{\"a}t W{\"u}rzburg}, year = {2005}, abstract = {Somites are repeated epithelial segments that are generated in a rhythmic manner from the presomitic mesoderm (PSM) in the embryonic tailbud. Later, they differentiate into skeletal muscle, cartilage and dermis. Somitogenesis is regulated by a complex interplay of different pathways. Notch/Delta signaling is one of the pathways well characterized in zebrafish through mutants affected in its different components. Previous work in mouse, chicken and zebrafish has shown that also additional components are required during somitogenesis, most importantly through an FGF and Retinoic acid (RA) gradient, as well as Wnt signaling. However, no zebrafish mutants with defects in these pathways showing specific somite malformations are described. This was explained by functional redundancies among related genes that have resulted from a whole genome duplication which occurred in a teleost fish ancestor 350 million years ago. As distinct duplicates exist in different teleost species, a large scale mutagenesis screen in the medaka (Oryzias latipes) has been performed successfully in Kyoto, Japan. I analyzed nine of the isolated medaka mutants that show variable aspects of somitic phenotypes. This includes a complete or partial loss of somite boundaries (e.g. bms and sne), somites with irregular sizes and shapes (e.g. krz and fsl) or partially fused and enlarged somites (e.g. dpk). Although some of these medaka mutants share characteristics with previously described zebrafish somite mutants, most of the mutants represent unique phenotypes, not obtained in the zebrafish screens. In-situ hybridization analyses with marker genes implicated in the segmentation clock (e.g. her7), establishment of anterior-posterior (A-P) polarity (e.g. mesp) and differentiation of somites (e.g. myf5, lfng) revealed that the medaka mutants can be separated into two classes. Class I shows defects in tailbud formation and PSM prepatterning, and lateron somite boundary formation was impaired in these mutants. A unique member of this class with a novel phenotype is the doppelkorn (dpk) mutant that has single fused or enlarged somites. This phenotype has not been reported till now in zebrafish somite mutants. In-situ analyses on dpk showed that stabilization of the cyclically expressed somitogenesis clock genes must be affected in this mutant. This is accompanied by a disrupted regulation of A-P polarity genes like mesp. This suggests that dpk is a mutant deficient in the wave front, which is necessary for the down-regulation of oscillating genes in the anterior PSM. Furthermore, as the initiation of oscillation of all three cyclic her genes was unaffected in dpk embryos, I could exclude that this mutant in affected in the Notch/Delta pathway. Another mutant that belongs to this class is the samidare (sam) mutant. Morphologically, sam mutants are similar to zebrafish after eight (aei). In both cases, the first 7-9 somites are formed properly, but after this somite formation ceases. Different to the situation in aei, sam mutant embryos presented an additional defect in the mid-hindbrain boundary (MHB) region. Similar MHB defects were described in the zebrafish fgf8 mutant acerebellar (ace). In ace zebrafish mutant, somites were only slightly defective, although FGF signaling has been shown to be important for somite formation in chicken, mouse and zebrafish. This was explained by functional redundancy between fgf8 and fgf24 ligands in the tailbud of zebrafish. Thus, it is interesting to suggest that the sam mutant, based on the parallel defects in somites and MHB, is a potential member of the FGF signaling pathway muatnts. It was shown that FGF plays a crucial role during MHB formation in medaka. In addition, I showed that fgf8 acts non-redundantly during tailbud formation and somitogenesis in medaka. Furthermore, I showed that FGF signaling regulates somite size also in medaka and that fgfr1 is the only FGF receptor expressed in the tailbud and somites. In class II medaka somite mutants, PSM prepatterning appears normal, whereas A-P polarity, boundary formation, epithelialization or the later differentiation of somites appears to be affected. Such mutants have not been isolated so far in zebrafish, mice or chicken. Therefore, medaka class II somite mutants seem to be a novel group of mutants that opens new perspectives to analyze A-P polarity regulation, determination and boundary formation in the presence of a normally functioning clock in the PSM. Identifying the encoding genes for all analyzed medaka somite mutants will contribute to the understanding of the molecular interactions of different signaling pathways involved during somitogenesis, and is expected to result in the identification of new components.}, subject = {Japank{\"a}rpfling}, language = {en} } @article{ElKeredySchleyerKoenigetal.2012, author = {El-Keredy, Amira and Schleyer, Michael and K{\"o}nig, Christian and Ekim, Aslihan and Gerber, Bertram}, title = {Behavioural Analyses of Quinine Processing in Choice, Feeding and Learning of Larval Drosophila}, series = {PLoS One}, volume = {7}, journal = {PLoS One}, number = {7}, doi = {10.1371/journal.pone.0040525}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-130811}, pages = {e40525}, year = {2012}, abstract = {Gustatory stimuli can support both immediate reflexive behaviour, such as choice and feeding, and can drive internal reinforcement in associative learning. For larval Drosophila, we here provide a first systematic behavioural analysis of these functions with respect to quinine as a study case of a substance which humans report as "tasting bitter". We describe the dose-effect functions for these different kinds of behaviour and find that a half-maximal effect of quinine to suppress feeding needs substantially higher quinine concentrations (2.0 mM) than is the case for internal reinforcement (0.6 mM). Interestingly, in previous studies (Niewalda et al. 2008, Schipanski et al 2008) we had found the reverse for sodium chloride and fructose/sucrose, such that dose-effect functions for those tastants were shifted towards lower concentrations for feeding as compared to reinforcement, arguing that the differences in dose-effect function between these behaviours do not reflect artefacts of the types of assay used. The current results regarding quinine thus provide a starting point to investigate how the gustatory system is organized on the cellular and/or molecular level to result in different behavioural tuning curves towards a bitter tastant.}, language = {en} } @article{ElHajjDittrichBoecketal.2016, author = {El Hajj, Nady and Dittrich, Marcus and B{\"o}ck, Julia and Kraus, Theo F. J. and Nanda, Indrajit and M{\"u}ller, Tobias and Seidmann, Larissa and Tralau, Tim and Galetzka, Danuta and Schneider, Eberhard and Haaf, Thomas}, title = {Epigenetic dysregulation in the developing Down syndrome cortex}, series = {Epigenetics}, volume = {11}, journal = {Epigenetics}, number = {8}, doi = {10.1080/15592294.2016.1192736}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-191239}, pages = {563-578}, year = {2016}, abstract = {Using Illumina 450K arrays, 1.85\% of all analyzed CpG sites were significantly hypermethylated and 0.31\% hypomethylated in fetal Down syndrome (DS) cortex throughout the genome. The methylation changes on chromosome 21 appeared to be balanced between hypo- and hyper-methylation, whereas, consistent with prior reports, all other chromosomes showed 3-11times more hyper- than hypo-methylated sites. Reduced NRSF/REST expression due to upregulation of DYRK1A (on chromosome 21q22.13) and methylation of REST binding sites during early developmental stages may contribute to this genome-wide excess of hypermethylated sites. Upregulation of DNMT3L (on chromosome 21q22.4) could lead to de novo methylation in neuroprogenitors, which then persists in the fetal DS brain where DNMT3A and DNMT3B become downregulated. The vast majority of differentially methylated promoters and genes was hypermethylated in DS and located outside chromosome 21, including the protocadherin gamma (PCDHG) cluster on chromosome 5q31, which is crucial for neural circuit formation in the developing brain. Bisulfite pyrosequencing and targeted RNA sequencing showed that several genes of PCDHG subfamilies A and B are hypermethylated and transcriptionally downregulated in fetal DS cortex. Decreased PCDHG expression is expected to reduce dendrite arborization and growth in cortical neurons. Since constitutive hypermethylation of PCDHG and other genes affects multiple tissues, including blood, it may provide useful biomarkers for DS brain development and pharmacologic targets for therapeutic interventions.}, language = {en} }