TY - THES A1 - Baumann, Dominika T1 - Zur Bedeutung von Mehrperspektivität in der Diagnostik kommunikativer Kompetenzen von Schüler:innen mit komplexen Kommunikationsbedürfnissen und sonderpädagogischem Unterstützungsbedarf im Schwerpunkt Geistige Entwicklung T1 - The importance of multiple perspectives in the assessment of communicative competencies of students with intellectual disabilities and complex communication needs N2 - Um Schüler:innen mit komplexen Kommunikationsbedürfnissen und sonderpädagogischem Unterstützungsbedarf im Schwerpunkt Geistige Entwicklung in ihrer Kommunikationsentwicklung unterstützen zu können, müssen zunächst ihre kommunikativen Kompetenzen eingeschätzt werden. Diese Kompetenzen können jedoch je nach Kommunikationspartner:in und Kontext erheblich variieren. Die Umweltabhängigkeit kommunikativer Kompetenzen sowie methodische Herausforderungen bei der Diagnostik kommunikativer Kompetenzen führen zu der Frage, wie Eltern, Lehrkräfte und andere Kommunikationspartner:innen die kommunikativen Kompetenzen dieser Schüler:innen einschätzen, welche Gemeinsamkeiten und Unterschiede zwischen den Einschätzungen bestehen und wie diese erklärt werden können. Mittels empirischer Daten eines mehrperspektivisch angelegten Fragebogens (N = 357) im Kontext des Forschungsprojektes SFGE II (Baumann et al., 2021) konnten signifikante Unterschiede zwischen der Einschätzung der Eltern und der Lehrkräfte bei vier der acht untersuchten Items zur Einschätzung der kommunikativen Kompetenzen nachgewiesen werden. Die unjustierte Interraterreliabilitätsanalyse konnte einen Einfluss der Familiensprache, der Diagnose sowie des Grades der Intelligenzminderung auf die Höhe der Reliabilität zwischen Eltern und Lehrkräften nachweisen. Die deskriptive Analyse von fünf Fallbeispielen aus zwei weiteren bayerischen Schulen mit sonderpädagogischem Schwerpunkt Geistige Entwicklung untersuchte die Einschätzungen weiterer Kommunikationspartner:innen und betonte vor allem die Bedeutung der UK-Expertise der Kommunikationspartner:innen sowie den Einfluss der aktuell genutzten Kommunikationsformen der Schüler:innen. Mit den Ergebnissen dieser Studie liegt erstmals ein empirischer Beleg für die unterschiedlichen Einschätzungen kommunikativer Kompetenzen zwischen Eltern und Lehrkräften von kaum und nicht lautsprachlich kommunizierenden Schüler:innen im sonderpädagogischen Schwerpunkt Geistige Entwicklung vor. Die umfassenden Analysen ermöglichen differenzierte Einblicke in das Einschätzungsverhalten verschiedener Kommunikationspartner:innen, liefern Hinweise zur Erklärung übereinstimmender sowie unterschiedlicher Einschätzungen und verweisen auf die Bedeutung von Mehrperspektivität im Kontext von UK-Diagnostik. N2 - To support children with complex communication needs and intellectual disabilities in their communicative development, we need to first assess their communicative competencies. These competencies however can vary significantly depending on the communication partner and context. This environmental dependency of communicative competencies as well as methodological challenges in assessing communicative competencies lead to the question of how parents, teachers, and other communication partners assess the communicative competencies of these students and how and why their assessments differ. To help answer these questions a multi-perspective questionnaire (N = 357) was conducted in the context of the study SFGE II (Baumann et al., 2021). The results revealed significant differences between parents' and teachers' assessments of four of the eight items examined in the assessment of communicative competence. Unadjusted interrater reliability analysis also demonstrated an influence of family language, diagnosis, and degree of intellectual disability on the level of reliability between parents and teachers. The descriptive analysis of five case studies from two other Bavarian special education schools examined the assessments of other communication partners and emphasized the importance of the communication partners’ AAC expertise as well as the influence of the currently used forms of communication of the students. The results of this study are the first empirical evidence of the different assessments of communicative competence between parents and teachers of students with intellectual disabilities and complex communication needs. The comprehensive analyses provide differentiated insights into the assessment behavior of various communication partners, provide information to explain both consistent and different assessments and point to the importance of multi-perspectivity in the context of AAC diagnostics. KW - Kommunikation KW - Geistige Behinderung KW - Sonderpädagogik KW - komplexe Kommunikationsbedürfnisse KW - Unterstützte Kommunikation KW - Mehrperspektivität KW - Beurteilerreliabilität KW - kommunikative Kompetenzen KW - complex communication needs KW - Augmentative and Alternative Communication KW - multi-perspectivity KW - interrater reliability KW - communicative competence KW - Urteilerübereinstimmung KW - Kommunikationshilfe KW - Beurteilerübereinstimmung Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-371955 ER - TY - THES A1 - Salehi, Saeede T1 - Axonal hnRNP R: regulation by Ptbp2 and functions in neurodegenerative disorders T1 - Axonales hnRNP R: Regulation durch Ptbp2 und Funktionen bei neurodegenerativen Erkrankungen N2 - Axon growth, a fundamental process of neuron development, is regulated by both intrinsic and external guidance signals. Impairment of axon growth and maintenance is implicated in the pathogenesis of neurodegenerative disorders such as Amyotrophic Lateral Sclerosis and Alzheimer’s disease (AD). Axon growth is driven by several post-transcriptional RNA processing mechanisms, including alternative splicing, polyadenylation, subcellular localization, and translation. These mechanisms are controlled by RNA-binding proteins (RBPs) through interacting with their target RNAs in a sequence-dependent manner. In this study, we investigate the cytosolic functions of two neuronal RBPs, Ptbp2 and hnRNP R, which are essential for axon growth in motoneurons. Polypyrimidine tract binding protein 2 (Ptbp2) contributes to neuronal differentiation and axonogenesis by modulating different splicing programs to adjust the level of proteins involved in these processes. While the nuclear functions of Ptbp2 in alternative splicing have been studied in more detail, the cytosolic roles of Ptbp2 associated with axon growth have remained elusive. In the first part of the study, we show that Ptbp2 is present in cytosolic fractions of motoneurons including axons and axon terminals. Depletion of Ptbp2 impairs axon growth and growth cone maturation in cultured embryonic mouse motoneurons. Moreover, Ptbp2 knockdown affects the level of piccolo protein in the growth cone of cultured motoneurons. We detect Ptbp2 as a top interactor of the 3' UTR of the Hnrnpr transcript encoding the RBP hnRNP R. This interaction results in axonal localization of and thereby local translation of Hnrnpr mRNA in motoneurons. Consequently, axonal synthesis of hnRNP R was diminished upon depletion of Ptbp2 in motoneurons. We present evidence that Ptbp2 through cooperation with translation factor eIF5A2 controls hnRNP R synthesis. Additionally, we observe that re-expression of hnRNP R in Ptbp2-deficient motoneurons rescued axon growth defect while Ptbp2 overexpression failed to normalize the axon elongation defect observed in hnRNP R-deficient motoneurons. Our findings pinpoint axonal synthesized hnRNP R as a mediator of Ptbp2 functions in axon growth. In the second part of this study, we identify hnRNP R binds to the 3' UTR of microtubule-associated tau (Mapt) transcript encoding tau protein and regulates the axonal translocation and translation of Mapt mRNA. Tau protein has a central role in neuronal microtubule assembly and stability. However, in AD, the accumulation of abnormally hyperphosphorylated tau protein leads to axon outgrowth defects. Loss of hnRNP R reduces axonal tau protein but not the total level of tau. We observe that the brains of 5xFAD mice, as a mouse model of AD, deficient for hnRNP R contain lower phospho-tau and amyloid-β plaques. Likewise, Neurons treated with blocking antisense oligonucleotides (ASO) to prevent binding of hnRNP R to Mapt mRNA show reduced axonal Mapt mRNA and consequently newly synthesized tau protein levels. We show that blocking Mapt mRNA transport to axons impairs axon elongation. Our data thus suggest that reducing tau levels selectively in axons, a major subcellular site of tangle formation, might represent a novel therapeutic approach for the treatment of AD. N2 - Axonwachstum ist ein grundlegender Prozess der Neuronenentwicklung und wird sowohl durch intrinsische als auch externe Leitsignale reguliert. Eine Beeinträchtigung des Axonwachstums und der Aufrechterhaltung von Axonen ist mit der Pathogenese neurodegenerativer Erkrankungen wie der Amyotrophen Lateralsklerose und der AlzheimerKrankheit (AD) verbunden. Mehrere posttranskriptionelle RNA-Verarbeitungsmechanismen, darunter alternatives Spleißen, Polyadenylierung, subzelluläre Lokalisierung und Translation, steuern das Axonwachstum. RNA-bindende Proteine (RBPs) steuern diese Mechanismen, indem sie sequenzabhängig mit ihren Ziel-RNAs interagieren. In dieser Studie untersuchen wir die zytosolischen Funktionen von zwei neuronalen RBPs, Ptbp2 und hnRNP R, die für das Axonwachstum in Motoneuronen essentiell sind. Das Polypyrimidin-Trakt-Bindungsprotein 2 (Ptbp2) trägt zur neuronalen Differenzierung und Axonogenese bei, indem es verschiedene Spleißprogramme moduliert, um die Menge der an diesen Prozessen beteiligten Proteine anzupassen. Während die nukleären Funktionen von Ptbp2 beim alternativen Spleißen detaillierter untersucht wurden, sind die zytosolischen Rollen von Ptbp2 im Zusammenhang mit dem Axonwachstum noch unklar. Im ersten Teil der Studie zeigen wir, dass Ptbp2 in zytosolischen Fraktionen von Motoneuronen einschließlich Axonen und Axonterminals vorhanden ist. Die Reduktion von Ptbp2 beeinträchtigt das Axonwachstum und die Reifung der Wachstumskegel in kultivierten embryonalen Motoneuronen von Mäusen. Darüber hinaus beeinflusst der Ptbp2-Knockdown den Gehalt an Piccolo-Protein im Wachstumskegel kultivierter Motoneuronen. Wir identifizierten Ptbp2 als Top-Interaktor der 3'-UTR des Hnrnpr-Transkripts, welches das RBP hnRNP R kodiert. Diese Interaktion führt zur axonalen Lokalisierung und damit zur lokalen Translation der Hnrnpr-mRNA in Motoneuronen. Folglich wurde die axonale Synthese von hnRNP R durch Depletion von Ptbp2 in Motoneuronen verringert. Wir legen Beweise dafür vor, dass Ptbp2 durch die Zusammenarbeit mit dem Translationsfaktor eIF5A2 die hnRNP R-Synthese steuert. Darüber hinaus beobachten wir, dass die erneute Expression von hnRNP R in Motoneuronen mit Ptbp2-Mangel den Axonwachstumsdefekt rettete, während die Überexpression von Ptbp2 den auch bei Motoneuronen mit hnRNP R-Mangel beobachteten Axonwachstumsdefekt nicht normalisieren konnte. Unsere Ergebnisse zeigen, dass axonal synthetisiertes hnRNP R ein Vermittler der Ptbp2-Funktionen beim Axonwachstum ist. Im zweiten Teil dieser Studie beobachteten wir, dass hnRNP R an die 3'-UTR des Mikrotubuliassoziierten Tau-Transkripts (Mapt) bindet, welches das Protein tau kodiert. Die hnRNP RMapt Interaktion bewirkt die axonale Translokation und Translation der Mapt-mRNA. Tau spielt eine zentrale Rolle beim Aufbau und der Stabilität neuronaler Mikrotubuli. Bei AD führt die Anhäufung von abnormal hyperphosphoryliertem tau-Protein jedoch zu neuronaler Degeneration. Der Verlust von hnRNP R verringert das axonale tau-Protein, jedoch nicht den Gesamtspiegel von tau. Wir beobachten, dass die Gehirne von 5xFAD-Mäusen, einem AD Mausmodell, durch Reduktion von hnRNP R geringere Mengen an Phospho-tau- und Amyloidβ-Plaques aufweisen. Ebenso zeigen Neuronen, die mit blockierenden ntisenseOligonukleotiden (ASO) behandelt wurden, um die Bindung von hnRNP R an Mapt-mRNA zu verhindern, verringerte axonale Mapt-mRNA Mengen und reduzierte Mengen an neu synthetisiertem tau-Protein. Unsere Daten legen daher nahe, dass die selektive Reduzierung des tau-Spiegels in Axonen, einem wichtigen subzellulären Ort der Neurofibrillenbildung, einen neuen therapeutischen Ansatz für die Behandlung der AD darstellen könnte. KW - Motoneuron KW - Axonal RNA localization KW - Axonal translation KW - Axon growth KW - Ptbp2 KW - Axonaler Transport KW - axonal transport KW - Nervendegeneration Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-371039 ER - TY - THES A1 - Reß-Müller, Lea T1 - Investigating Dynamics of Biradicals and Chiral Excitons Using Transient Absorption and Time-Resolved Circular Dichroism Spectroscopy T1 - Untersuchung der Dynamiken von Biradikalen und chiralen Exzitonen durch die Verwendung von transienter Absorptions- und Zeitaufgelöster Zirkulardichroismus-Spektroskopie N2 - In this work, two techniques, based on the established method of pump--probe spectroscopy were used to investigate the properties of molecular systems in the liquid phase within the visible spectral wavelength range. The first technique is standard transient absorption (TA) spectroscopy which was applied to a diazo-precursor to identify the formation of a biradical in an inert solvent after UV excitation. With the combination of EPR spectroscopy and quantum chemical calculations, the formation of a biradical in an unpolar and non-protic solvent was proven. Besides, in the presence of air or a polar and protic solvent, the biradical reacts ultrafast to various side products. The second technique is time-resolved circular dichroism (TRCD) spectroscopy, which was performed in two different ways. The first approach based on a pulse-enantiomer (PE) setup, where an initially circularly polarized pulse was split into two pulses, of which one was mirrored under normal incidence, to flip its polarization. The result was two pulses with mirrored polarization states that propagate collinearly to the sample as left and right circularly polarized probe pulses. The alignment procedure as well as the drawbacks of this setup are described in detail. However, a new TRCD setup was built that used a polarization grating to get left and right circularly polarized pulses. With the experiences of working with the PE setup, the new TRCD setup could be optimized so that TRCD spectra of a chiral squaraine polymer could be measured. With the help of quantum chemical calculations, the signals were assigned to exciton dynamics that describe spatial and energetic rearrangements of the excitation energy. The alignment and the measurement procedures to perform TRCD spectroscopy with the new setup are described in detail for future experiments. N2 - In dieser Arbeit wurden zwei Techniken, die auf der etablierten Methode der Anrege-Abfrage-Spektroskopie beruhen, zur Untersuchung der Eigenschaften molekularer Systeme in der Flüssigphase im sichtbaren Wellenlängenbereich eingesetzt. Die erste Technik ist die standardmäßige transiente Absorptionsspektroskopie, die auf einen Diazovorläufer angewendet wurde, um die Bildung eines Biradikals in einem inerten Lösungsmittel nach UV-Anregung zu identifizieren. Durch die Kombination von EPR-Spektroskopie und quantenchemischen Berechnungen konnte die Bildung eines Biradikals in einem unpolaren und nicht-protischen Lösungsmittel nachgewiesen werden. Außerdem reagiert das Biradikal in Gegenwart von Luft oder einem polaren und protischen Lösungsmittel ultraschnell zu verschiedenen Nebenprodukten. Die zweite Technik ist die zeitaufgelöste Zirkulardichroismus (TRCD)-Spektroskopie , die auf zwei verschiedene Arten durchgeführt wurde. Der erste Ansatz basiert auf einem Puls-Enantiomer (PE)-Aufbau, bei dem ein ursprünglich zirkular polarisierter Puls in zwei Pulse aufgespalten wurde, von denen einer unter nach einer Reflexion von 90$^\circ$ zur Piegeloberfläche gespiegelt wurde, um seine Polarisation umzukehren. Das Ergebnis waren zwei Pulse mit gespiegelten Polarisationszuständen, die sich kollinear als links- und rechtszirkular polarisierte Abfragepulse ausbreiten. Das Justageverfahren sowie die Nachteile dieses Aufbaus sind ausführlich beschrieben. Außerdem wurde ein neuer TRCD-Aufbau verwirklicht, der ein Polarisationsgitter verwendet, um links- und rechtszirkular polarisierte Pulse zu erhalten. Mit den Erfahrungen aus der Arbeit mit dem PE-Aufbau konnte der neue TRCD-Aufbau so optimiert werden, dass TRCD-Spektren eines chiralen Squaraine-Polymers gemessen werden konnten. Mit Hilfe von quantenchemischen Berechnungen wurden die Signale der Exzitonendynamik zugeordnet, die räumliche und energetische Umlagerungen der Anregungsenergie beschreiben. Die Justage und das Messverfahren zur Durchführung der TRCD-Spektroskopie mit dem neuen Aufbau werden für zukünftige Experimente detailliert beschrieben. KW - Zirkulardichroismus KW - Ultrakurzzeitspektroskopie KW - Biradikal KW - Exziton KW - Transiente Absorption KW - Zeitaufgelöste Zirkulardichroismus Spektroskopie KW - zirkulare Polarisation KW - Angeregte Zustände KW - transient absorption KW - time-resolved circular dichroism spectroscopy KW - circular polarization KW - chirality KW - excited states KW - Chiralität Y1 - 2024 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-370333 ER - TY - JOUR A1 - Shao, Yi-Ming A1 - Ma, Xiaohua A1 - Paira, Priyankar A1 - Tan, Aaron A1 - Herr, Deron Raymond A1 - Lim, Kah Leong A1 - Ng, Chee Hoe A1 - Venkatesan, Gopalakrishnan A1 - Klotz, Karl-Norbert A1 - Federico, Stephanie A1 - Spalluto, Giampiero A1 - Cheong, Siew Lee A1 - Chen, Yu Zong A1 - Pastorin, Giorgia T1 - Discovery of indolylpiperazinylpyrimidines with dual-target profiles at adenosine A2A and dopamine D2 receptors for Parkinson's disease treatment JF - PLoS ONE N2 - Parkinson’s disease (PD) is a neurodegenerative disorder characterized by progressive loss of dopaminergic neurons in the substantia nigra of the human brain, leading to depletion of dopamine production. Dopamine replacement therapy remains the mainstay for attenuation of PD symptoms. Nonetheless, the potential benefit of current pharmacotherapies is mostly limited by adverse side effects, such as drug-induced dyskinesia, motor fluctuations and psychosis. Non-dopaminergic receptors, such as human A2A adenosine receptors, have emerged as important therapeutic targets in potentiating therapeutic effects and reducing the unwanted side effects. In this study, new chemical entities targeting both human A2A adenosine receptor and dopamine D2 receptor were designed and evaluated. Two computational methods, namely support vector machine (SVM) models and Tanimoto similarity-based clustering analysis, were integrated for the identification of compounds containing indole-piperazine-pyrimidine (IPP) scaffold. Subsequent synthesis and testing resulted in compounds 5 and 6, which acted as human A2A adenosine receptor binders in the radioligand competition assay (Ki = 8.7–11.2 μM) as well as human dopamine D2 receptor binders in the artificial cell membrane assay (EC50 = 22.5–40.2 μM). Moreover, compound 5 showed improvement in movement and mitigation of the loss of dopaminergic neurons in Drosophila models of PD. Furthermore, in vitro toxicity studies on compounds 5 and 6 did not reveal any mutagenicity (up to 100 μM), hepatotoxicity (up to 30 μM) or cardiotoxicity (up to 30 μM). Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-237766 VL - 13 ER - TY - JOUR A1 - Förster, Sabine A1 - Koziol, Uriel A1 - Schäfer, Tina A1 - Duvoisin, Raphael A1 - Cailliau, Katia A1 - Vanderstraete, Mathieu A1 - Dissous, Colette A1 - Brehm, Klaus T1 - The role of fibroblast growth factor signalling in Echinococcus multilocularis development and host-parasite interaction JF - PLoS Neglected Tropical Diseases N2 - Background Alveolar echinococcosis (AE) is a lethal zoonosis caused by the metacestode larva of the tapeworm Echinococcus multilocularis. The infection is characterized by tumour-like growth of the metacestode within the host liver, leading to extensive fibrosis and organ-failure. The molecular mechanisms of parasite organ tropism towards the liver and influences of liver cytokines and hormones on parasite development are little studied to date. Methodology/Principal findings We show that the E. multilocularis larval stage expresses three members of the fibroblast growth factor (FGF) receptor family with homology to human FGF receptors. Using the Xenopus expression system we demonstrate that all three Echinococcus FGF receptors are activated in response to human acidic and basic FGF, which are present in the liver. In all three cases, activation could be prevented by addition of the tyrosine kinase (TK) inhibitor BIBF 1120, which is used to treat human cancer. At physiological concentrations, acidic and basic FGF significantly stimulated the formation of metacestode vesicles from parasite stem cells in vitro and supported metacestode growth. Furthermore, the parasite’s mitogen activated protein kinase signalling system was stimulated upon addition of human FGF. The survival of metacestode vesicles and parasite stem cells were drastically affected in vitro in the presence of BIBF 1120. Conclusions/Significance Our data indicate that mammalian FGF, which is present in the liver and upregulated during fibrosis, supports the establishment of the Echinococcus metacestode during AE by acting on an evolutionarily conserved parasite FGF signalling system. These data are valuable for understanding molecular mechanisms of organ tropism and host-parasite interaction in AE. Furthermore, our data indicate that the parasite’s FGF signalling systems are promising targets for the development of novel drugs against AE. Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-228190 VL - 13 ER - TY - JOUR A1 - Nagy, Dóra A1 - Cusumano, Paola A1 - Andreatta, Gabriele A1 - Martin Anduaga, Ane A1 - Hermann-Luibl, Christiane A1 - Reinhard, Nils A1 - Gesto, João A1 - Wegener, Christian A1 - Mazzotta, Gabriella A1 - Rosato, Ezio A1 - Kyriacou, Charalambos P. A1 - Helfrich-Förster, Charlotte A1 - Costa, Rodolfo T1 - Peptidergic signaling from clock neurons regulates reproductive dormancy in Drosophila melanogaster JF - PLoS Genetics N2 - With the approach of winter, many insects switch to an alternative protective developmental program called diapause. Drosophila melanogaster females overwinter as adults by inducing a reproductive arrest that is characterized by inhibition of ovarian development at previtellogenic stages. The insulin producing cells (IPCs) are key regulators of this process, since they produce and release insulin-like peptides that act as diapause-antagonizing hormones. Here we show that in D. melanogaster two neuropeptides, Pigment Dispersing Factor (PDF) and short Neuropeptide F (sNPF) inhibit reproductive arrest, likely through modulation of the IPCs. In particular, genetic manipulations of the PDF-expressing neurons, which include the sNPF-producing small ventral Lateral Neurons (s-LNvs), modulated the levels of reproductive dormancy, suggesting the involvement of both neuropeptides. We expressed a genetically encoded cAMP sensor in the IPCs and challenged brain explants with synthetic PDF and sNPF. Bath applications of both neuropeptides increased cAMP levels in the IPCs, even more so when they were applied together, suggesting a synergistic effect. Bath application of sNPF additionally increased Ca2+ levels in the IPCs. Our results indicate that PDF and sNPF inhibit reproductive dormancy by maintaining the IPCs in an active state. Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-231681 VL - 15 ER - TY - JOUR A1 - Li, Ying H. A1 - Liu, Xianhui A1 - Vanselow, Jens T. A1 - Zheng, Haiyan A1 - Schlosser, Andreas A1 - Chiu, Joanna C. T1 - O-GlcNAcylation of PERIOD regulates its interaction with CLOCK and timing of circadian transcriptional repression JF - PLoS Genetics N2 - Circadian clocks coordinate time-of-day-specific metabolic and physiological processes to maximize organismal performance and fitness. In addition to light and temperature, which are regarded as strong zeitgebers for circadian clock entrainment, metabolic input has now emerged as an important signal for clock entrainment and modulation. Circadian clock proteins have been identified to be substrates of O-GlcNAcylation, a nutrient sensitive post-translational modification (PTM), and the interplay between clock protein O-GlcNAcylation and other PTMs is now recognized as an important mechanism by which metabolic input regulates circadian physiology. To better understand the role of O-GlcNAcylation in modulating clock protein function within the molecular oscillator, we used mass spectrometry proteomics to identify O-GlcNAcylation sites of PERIOD (PER), a repressor of the circadian transcriptome and a critical biochemical timer of the Drosophila clock. In vivo functional characterization of PER O-GlcNAcylation sites indicates that O-GlcNAcylation at PER(S942) reduces interactions between PER and CLOCK (CLK), the key transcriptional activator of clock-controlled genes. Since we observe a correlation between clock-controlled daytime feeding activity and higher level of PER O-GlcNAcylation, we propose that PER(S942) O-GlcNAcylation during the day functions to prevent premature initiation of circadian repression phase. This is consistent with the period-shortening behavioral phenotype of per(S942A) flies. Taken together, our results support that clock-controlled feeding activity provides metabolic signals to reinforce light entrainment to regulate circadian physiology at the post-translational level. The interplay between O-GlcNAcylation and other PTMs to regulate circadian physiology is expected to be complex and extensive, and reach far beyond the molecular oscillator. Y1 - 2019 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-236826 VL - 15 ER - TY - JOUR A1 - del Olmo Toledo, Valentina A1 - Puccinelli, Robert A1 - Fordyce, Polly M. A1 - Pérez, J. Christian T1 - Diversification of DNA binding specificities enabled SREBP transcription regulators to expand the repertoire of cellular functions that they govern in fungi JF - PLoS Genetics N2 - The Sterol Regulatory Element Binding Proteins (SREBPs) are basic-helix-loop-helix transcription regulators that control the expression of sterol biosynthesis genes in higher eukaryotes and some fungi. Surprisingly, SREBPs do not regulate sterol biosynthesis in the ascomycete yeasts (Saccharomycotina) as this role was handed off to an unrelated transcription regulator in this clade. The SREBPs, nonetheless, expanded in fungi such as the ascomycete yeasts Candida spp., raising questions about their role and evolution in these organisms. Here we report that the fungal SREBPs diversified their DNA binding preferences concomitantly with an expansion in function. We establish that several branches of fungal SREBPs preferentially bind non-palindromic DNA sequences, in contrast to the palindromic DNA motifs recognized by most basic-helix-loop-helix proteins (including SREBPs) in higher eukaryotes. Reconstruction and biochemical characterization of the likely ancestor protein suggest that an intrinsic DNA binding promiscuity in the family was resolved by alternative mechanisms in different branches of fungal SREBPs. Furthermore, we show that two SREBPs in the human commensal yeast Candida albicans drive a transcriptional cascade that inhibits a morphological switch under anaerobic conditions. Preventing this morphological transition enhances C. albicans colonization of the mammalian intestine, the fungus’ natural niche. Thus, our results illustrate how diversification in DNA binding preferences enabled the functional expansion of a family of eukaryotic transcription regulators. Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-228983 VL - 14 ER - TY - JOUR A1 - Lu, Yuan A1 - Boswell, Mikki A1 - Boswell, William A1 - Kneitz, Susanne A1 - Klotz, Barbara A1 - Savage, Markita A1 - Salinas, Raquel A1 - Marks, Rebacca A1 - Regneri, Janine A1 - Postlethwait, John A1 - Warren, Wesley C. A1 - Schartl, Manfred A1 - Walter, Ronald T1 - Gene expression variation and parental allele inheritance in a Xiphophorus interspecies hybridization model JF - PLoS Genetics N2 - Understanding the genetic mechanisms underlying segregation of phenotypic variation through successive generations is important for understanding physiological changes and disease risk. Tracing the etiology of variation in gene expression enables identification of genetic interactions, and may uncover molecular mechanisms leading to the phenotypic expression of a trait, especially when utilizing model organisms that have well-defined genetic lineages. There are a plethora of studies that describe relationships between gene expression and genotype, however, the idea that global variations in gene expression are also controlled by genotype remains novel. Despite the identification of loci that control gene expression variation, the global understanding of how genome constitution affects trait variability is unknown. To study this question, we utilized Xiphophorus fish of different, but tractable genetic backgrounds (inbred, F1 interspecies hybrids, and backcross hybrid progeny), and measured each individual’s gene expression concurrent with the degrees of inter-individual expression variation. We found, (a) F1 interspecies hybrids exhibited less variability than inbred animals, indicting gene expression variation is not affected by the fraction of heterozygous loci within an individual genome, and (b), that mixing genotypes in backcross populations led to higher levels of gene expression variability, supporting the idea that expression variability is caused by heterogeneity of genotypes of cis or trans loci. In conclusion, heterogeneity of genotype, introduced by inheritance of different alleles, accounts for the largest effects on global phenotypical variability. Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-237318 VL - 14 ER - TY - JOUR A1 - El Mouali, Youssef A1 - Gaviria-Cantin, Tania A1 - Sánchez-Romero, María Antonia A1 - Gibert, Marta A1 - Westermann, Alexander J. A1 - Vogel, Jörg A1 - Balsalobre, Carlos T1 - CRP-cAMP mediates silencing of Salmonella virulence at the post-transcriptional level JF - PLoS Genetics N2 - Invasion of epithelial cells by Salmonella enterica requires expression of genes located in the pathogenicity island I (SPI-1). The expression of SPI-1 genes is very tightly regulated and activated only under specific conditions. Most studies have focused on the regulatory pathways that induce SPI-1 expression. Here, we describe a new regulatory circuit involving CRP-cAMP, a widely established metabolic regulator, in silencing of SPI-1 genes under non-permissive conditions. In CRP-cAMP-deficient strains we detected a strong upregulation of SPI-1 genes in the mid-logarithmic growth phase. Genetic analyses revealed that CRP-cAMP modulates the level of HilD, the master regulator of Salmonella invasion. This regulation occurs at the post-transcriptional level and requires the presence of a newly identified regulatory motif within the hilD 3’UTR. We further demonstrate that in Salmonella the Hfq-dependent sRNA Spot 42 is under the transcriptional repression of CRP-cAMP and, when this transcriptional repression is relieved, Spot 42 exerts a positive effect on hilD expression. In vivo and in vitro assays indicate that Spot 42 targets, through its unstructured region III, the 3’UTR of the hilD transcript. Together, our results highlight the biological relevance of the hilD 3’UTR as a hub for post-transcriptional control of Salmonella invasion gene expression. Y1 - 2018 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-226614 VL - 14 ER -