TY - JOUR A1 - Widmann, Annekathrin A1 - Artinger, Marc A1 - Biesinger, Lukas A1 - Boepple, Kathrin A1 - Peters, Christina A1 - Schlechter, Jana A1 - Selcho, Mareike A1 - Thum, Andreas S. T1 - Genetic Dissection of Aversive Associative Olfactory Learning and Memory in Drosophila Larvae JF - PLoS Genetics N2 - Memory formation is a highly complex and dynamic process. It consists of different phases, which depend on various neuronal and molecular mechanisms. In adult Drosophila it was shown that memory formation after aversive Pavlovian conditioning includes—besides other forms—a labile short-term component that consolidates within hours to a longer-lasting memory. Accordingly, memory formation requires the timely controlled action of different neuronal circuits, neurotransmitters, neuromodulators and molecules that were initially identified by classical forward genetic approaches. Compared to adult Drosophila, memory formation was only sporadically analyzed at its larval stage. Here we deconstruct the larval mnemonic organization after aversive olfactory conditioning. We show that after odor-high salt conditioning larvae form two parallel memory phases; a short lasting component that depends on cyclic adenosine 3’5’-monophosphate (cAMP) signaling and synapsin gene function. In addition, we show for the first time for Drosophila larvae an anesthesia resistant component, which relies on radish and bruchpilot gene function, protein kinase C activity, requires presynaptic output of mushroom body Kenyon cells and dopamine function. Given the numerical simplicity of the larval nervous system this work offers a unique prospect for studying memory formation of defined specifications, at full-brain scope with single-cell, and single-synapse resolution. KW - genetic dissection KW - Drosophila KW - memory formation Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-166672 VL - 12 IS - 10 ER - TY - JOUR A1 - Vaze, Koustubh M. A1 - Helfrich-Förster, Charlotte T1 - Drosophila ezoana uses an hour-glass or highly damped circadian clock for measuring night length and inducing diapause JF - Physiological Entomology N2 - Insects inhabiting the temperate zones measure seasonal changes in day or night length to enter the overwintering diapause. Diapause induction occurs after the duration of the night exceeds a critical night length (CNL). Our understanding of the time measurement mechanisms is continuously evolving subsequent to Bünning’s proposal that circadian systems play the clock role in photoperiodic time measurement (Bünning, 1936). Initially, the photoperiodic clocks were considered to be either based on circadian oscillators or on simple hour-glasses, depending on ‘positive’ or ‘negative’ responses in Nanda–Hamner and Bünsow experiments (Nanda & Hammer, 1958; Bünsow, 1960). However, there are also species whose responses can be regarded as neither ‘positive’, nor as ‘negative’, such as the Northern Drosophila species Drosophila ezoana, which is investigated in the present study. In addition, modelling efforts show that the ‘positive’ and ‘negative’ Nanda–Hamner responses can also be provoked by circadian oscillators that are damped to different degrees: animals with highly sustained circadian clocks will respond ‘positive’ and those with heavily damped circadian clocks will respond ‘negative’. In the present study, an experimental assay is proposed that characterizes the photoperiodic oscillators by determining the effects of non-24-h light/dark cycles (T-cycles) on critical night length. It is predicted that there is (i) a change in the critical night length as a function of T-cycle period in sustained-oscillator-based clocks and (ii) a fxed night-length measurement (i.e. no change in critical night length) in damped-oscillator-based clocks. Drosophila ezoana flies show a critical night length of approximately 7 h irrespective of T-cycle period, suggesting a damped-oscillator-based photoperiodic clock. The conclusion is strengthened by activity recordings revealing that the activity rhythm of D. ezoana flies also dampens in constant darkness. KW - photoperiodic time mesurement KW - wyeomyia smithii KW - protophormia terraenovae KW - immunoreactive neurons KW - geographical variation KW - reproductive diapause KW - rhythmic components KW - locomotor activity KW - circadian clock KW - damped-oscillator-model of photoperiodic clock KW - diapause KW - Drosophila KW - hour-glass KW - pitcher-plant mosquito KW - bug riptortus-pedestris KW - Nanda-Hamner KW - photoperiodism Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-204278 VL - 41 IS - 4 ER - TY - JOUR A1 - Senthilan, Pingkalai R. A1 - Helfrich-Förster, Charlotte T1 - Rhodopsin 7-The unusual Rhodopsin in Drosophila JF - PeerJ N2 - Rhodopsins are the major photopigments in the fruit fly Drosophila melanogaster. Drosophila express six well-characterized Rhodopsins (Rh1–Rh6) with distinct absorption maxima and expression pattern. In 2000, when the Drosophila genome was published, a novel Rhodopsin gene was discovered: Rhodopsin 7 (Rh7). Rh7 is highly conserved among the Drosophila genus and is also found in other arthropods. Phylogenetic trees based on protein sequences suggest that the seven Drosophila Rhodopsins cluster in three different groups. While Rh1, Rh2 and Rh6 form a “vertebrate-melanopsin-type”–cluster, and Rh3, Rh4 and Rh5 form an “insect-type”-Rhodopsin cluster, Rh7 seem to form its own cluster. Although Rh7 has nearly all important features of a functional Rhodopsin, it differs from other Rhodopsins in its genomic and structural properties, suggesting it might have an overall different role than other known Rhodopsins. KW - vision KW - Drosophila KW - Opsins KW - Rhodopsins KW - phototransduction Y1 - 2016 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-177998 VL - 4 ER - TY - JOUR A1 - Selcho, Mareike A1 - Millán, Carola A1 - Palacios-Muñoz, Angelina A1 - Ruf, Franziska A1 - Ubillo, Lilian A1 - Chen, Jiangtian A1 - Bergmann, Gregor A1 - Ito, Chihiro A1 - Silva, Valeria A1 - Wegener, Christian A1 - Ewer, John T1 - Central and peripheral clocks are coupled by a neuropeptide pathway in Drosophila JF - Nature Communications N2 - Animal circadian clocks consist of central and peripheral pacemakers, which are coordinated to produce daily rhythms in physiology and behaviour. Despite its importance for optimal performance and health, the mechanism of clock coordination is poorly understood. Here we dissect the pathway through which the circadian clock of Drosophila imposes daily rhythmicity to the pattern of adult emergence. Rhythmicity depends on the coupling between the brain clock and a peripheral clock in the prothoracic gland (PG), which produces the steroid hormone, ecdysone. Time information from the central clock is transmitted via the neuropeptide, sNPF, to non-clock neurons that produce the neuropeptide, PTTH. These secretory neurons then forward time information to the PG clock. We also show that the central clock exerts a dominant role on the peripheral clock. This use of two coupled clocks could serve as a paradigm to understand how daily steroid hormone rhythms are generated in animals. KW - circadian clock KW - Drosophila KW - neuropeptide pathway KW - peripheral clocks KW - central clocks Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170831 VL - 8 IS - 15563 ER - TY - JOUR A1 - Pütz, Stephanie M. A1 - Kram, Jette A1 - Rauh, Elisa A1 - Kaiser, Sophie A1 - Toews, Romy A1 - Lueningschroer-Wang, Yi A1 - Rieger, Dirk A1 - Raabe, Thomas T1 - Loss of p21-activated kinase Mbt/PAK4 causes Parkinson-like symptoms in Drosophila JF - Disease Models & Mechanisms N2 - Parkinson's disease (PD) provokes bradykinesia, resting tremor, rigidity and postural instability, and also non-motor symptoms such as depression, anxiety, sleep and cognitive impairments. Similar phenotypes can be induced in Drosophila melanogaster through modification of PD-relevant genes or the administration of PD inducing toxins. Recent studies correlated deregulation of human p21-activated kinase 4 (PAK4) with PD, leaving open the question of a causative relationship of mutations in this gene for manifestation of PD symptoms. To determine whether flies lacking the PAK4 homolog Mushroom bodies tiny (Mbt) show PD-like phenotypes, we tested for a variety of PD criteria. Here, we demonstrate that mbt mutant flies show PD-like phenotypes including age-dependent movement deficits, reduced life expectancy and fragmented sleep. They also react to a stressful situation with higher immobility, indicating an influence of Mbt on emotional behavior. Loss of Mbt function has a negative effect on the number of dopaminergic protocerebral anterior medial (PAM) neurons, most likely caused by a proliferation defect of neural progenitors. The age-dependent movement deficits are not accompanied by a corresponding further loss of PAM neurons. Previous studies highlighted the importance of a small PAM subgroup for age-dependent PD motor impairments. We show that impaired motor skills are caused by a lack of Mbt in this PAM subgroup. In addition, a broader re-expression of Mbt in PAM neurons improves life expectancy. Conversely, selective Mbt knockout in the same cells shortens lifespan. We conclude that mutations in Mbt/PAK4 can play a causative role in the development of PD phenotypes. KW - Sleep fragmentation KW - Life expectancy KW - Emotional behavior KW - Dopaminergic PAM cluster neurons KW - Drosophila KW - Parkinson's disease KW - Mbt KW - PAK4 KW - Negative geotaxis Y1 - 2021 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-259222 VL - 14 IS - 6 ER - TY - JOUR A1 - Herter, Eva K. A1 - Stauch, Maria A1 - Gallant, Maria A1 - Wolf, Elmar A1 - Raabe, Thomas A1 - Gallant, Peter T1 - snoRNAs are a novel class of biologically relevant Myc targets JF - BMC Biology N2 - Background Myc proteins are essential regulators of animal growth during normal development, and their deregulation is one of the main driving factors of human malignancies. They function as transcription factors that (in vertebrates) control many growth- and proliferation-associated genes, and in some contexts contribute to global gene regulation. Results We combine chromatin immunoprecipitation-sequencing (ChIPseq) and RNAseq approaches in Drosophila tissue culture cells to identify a core set of less than 500 Myc target genes, whose salient function resides in the control of ribosome biogenesis. Among these genes we find the non-coding snoRNA genes as a large novel class of Myc targets. All assayed snoRNAs are affected by Myc, and many of them are subject to direct transcriptional activation by Myc, both in Drosophila and in vertebrates. The loss of snoRNAs impairs growth during normal development, whereas their overexpression increases tumor mass in a model for neuronal tumors. Conclusions This work shows that Myc acts as a master regulator of snoRNP biogenesis. In addition, in combination with recent observations of snoRNA involvement in human cancer, it raises the possibility that Myc’s transforming effects are partially mediated by this class of non-coding transcripts. KW - Drosophila KW - ribosome KW - snoRNA KW - Myc Transcription KW - growth Y1 - 2015 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-124956 VL - 13 IS - 25 ER - TY - JOUR A1 - Chen, Yi-chun A1 - Mishra, Dushyant A1 - Gläß, Sebastian A1 - Gerber, Bertram T1 - Behavioral Evidence for Enhanced Processing of the Minor Component of Binary Odor Mixtures in Larval Drosophila JF - Frontiers in Psychology N2 - A fundamental problem in deciding between mutually exclusive options is that the decision needs to be categorical although the properties of the options often differ but in grade. We developed an experimental handle to study this aspect of behavior organization. Larval Drosophila were trained such that in one set of animals odor A was rewarded, but odor B was not (A+/B), whereas a second set of animals was trained reciprocally (A/B+). We then measured the preference of the larvae either for A, or for B, or for “morphed” mixtures of A and B, that is for mixtures differing in the ratio of the two components. As expected, the larvae showed higher preference when only the previously rewarded odor was presented than when only the previously unrewarded odor was presented. For mixtures of A and B that differed in the ratio of the two components, the major component dominated preference behavior—but it dominated less than expected from a linear relationship between mixture ratio and preference behavior. This suggests that a minor component can have an enhanced impact in a mixture, relative to such a linear expectation. The current paradigm may prove useful in understanding how nervous systems generate discrete outputs in the face of inputs that differ only gradually. KW - learning KW - memory KW - perception KW - compound conditioning KW - decision-making KW - Drosophila Y1 - 2017 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-170011 VL - 8 IS - 1923 ER - TY - JOUR A1 - Bogdan, Sven A1 - Schultz, Jörg A1 - Grosshans, Jörg T1 - Formin’ cellular structures: Physiological roles of Diaphanous (Dia) in actin dynamics JF - Communicative & Integrative Biology N2 - Members of the Diaphanous (Dia) protein family are key regulators of fundamental actin driven cellular processes, which are conserved from yeast to humans. Researchers have uncovered diverse physiological roles in cell morphology, cell motility, cell polarity, and cell division, which are involved in shaping cells into tissues and organs. The identification of numerous binding partners led to substantial progress in our understanding of the differential functions of Dia proteins. Genetic approaches and new microscopy techniques allow important new insights into their localization, activity, and molecular principles of regulation. KW - Drosophila KW - cytoskeleton KW - actin KW - nucleator KW - development KW - formin Y1 - 2013 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-121305 VL - 6 IS - e27634 ER -