Le Centre national du livre et sa politique de soutien au développement des collections de livres et de revues en bibliothèques

Les bibliothèques sont inscrites dans un dispositif d’aides thématiques. Il n\u27est pas toujours aisé d\u27en suivre les évolutions ni de s’en saisir à temps. Un coup de projecteur salutaire avant la fin de l’exercice 2010

A Statistically Representative Atlas for Mapping Neuronal Circuits in the Drosophila Adult Brain

Published: 23 March 2018The Supplementary Material for this article can be found online at: https://www.frontiersin.org/articles/10.3389/fninf.2018.00013/full#supplementary-material Supplementary Figure 1. 3D renderings of the 14 regions used for quantitative evaluation of atlas performances in segmentation and registration tasks. The 14 regions shown here were extracted from the atlas of Ito et al. (2014) that has been registered onto the group-wise inter-sex atlas (available from http://fruitfly.tefor.net). Supplementary Figure 2. Selected lines from the Janelia Farm collection showing an overlap value with the search pattern ranking among the first 50 for at least three of the five PDF profiles. (Left) GAL4-driven GFP profile registered on the standard brain. (Right) overlap between the first PDF profile and the GAL4-driven GFP profile. Numbers refer to Janelia Farm lines with associated gene names. Scale bar: 20 μm. Supplementary Table 1. Results of the 3D space query for each of the five PDF profiles. Overlap values are indicated for each Janelia Farm line and the corresponding gene name (FlyBase nomenclature) is indicated for the overlap values ranking among the first 50 for at least three of the five PDF profiles (blue). Bold names correspond to the three lines shown in Figure 10. Supplementary Movie 1. Animated rendering of the group-wise inter-sex atlas. Successively: nc82 template image (2D sections then 3D volume rendering, opaque then transparent); label image (3D surface rendering of anatomical regions, defined following Ito et al. 2014); six registered patterns of GAL4-GFP expression (3D surface rendering of intensity-thresholded pattern images); same patterns (left half of the brain) with the anatomical regions (right half of the brain).Imaging the expression patterns of reporter constructs is a powerful tool to dissect the neuronal circuits of perception and behavior in the adult brain of Drosophila, one of the major models for studying brain functions. To date, several Drosophila brain templates and digital atlases have been built to automatically analyze and compare collections of expression pattern images. However, there has been no systematic comparison of performances between alternative atlasing strategies and registration algorithms. Here, we objectively evaluated the performance of different strategies for building adult Drosophila brain templates and atlases. In addition, we used state-of-the-art registration algorithms to generate a new group-wise inter-sex atlas. Our results highlight the benefit of statistical atlases over individual ones and show that the newly proposed inter-sex atlas outperformed existing solutions for automated registration and annotation of expression patterns. Over 3,000 images from the Janelia Farm FlyLight collection were registered using the proposed strategy. These registered expression patterns can be searched and compared with a new version of the BrainBaseWeb system and BrainGazer software. We illustrate the validity of our methodology and brain atlas with registration-based predictions of expression patterns in a subset of clock neurons. The described registration framework should benefit to brain studies in Drosophila and other insect species.IA-C, TM, NM, FS, and AJ were funded by the Tefor Infrastructure under the Investments for the Future program of the French National Research Agency (Grant #ANR-11-INBS-0014). FR was supported by INSERM. Work at Institut des Neurosciences Paris-Saclay was supported by ANR Infrastructure Tefor and by ANR ClockEye(#ANR-14-CE13-0034-01). JI was supported by the Spanish Ministry of Economy and Competitiveness (TEC2014-51882-P), the European Union's Horizon 2020 research and innovation programme (Marie Sklodowska-Curie grant 654911, project THALAMODEL), and the European Research Council (ERC Starting Grant no. 677697 BUNGEE-TOOLS). VRVis (KB, FS) is funded by BMVIT, BMWFW, Styria, SFG and Vienna Business Agency in the scope of COMET - Competence Centers for Excellent Technologies (854174) which is managed by FFG. The Institut Jean-Pierre Bourgin benefits from the support of the LabEx Saclay Plant Sciences-SPS (#ANR-10-LABX-0040-SPS)

Light Activates Output from Evening Neurons and Inhibits Output from Morning Neurons in the Drosophila Circadian Clock

Animal circadian clocks are based on multiple oscillators whose interactions allow the daily control of complex behaviors. The Drosophila brain contains a circadian clock that controls rest–activity rhythms and relies upon different groups of PERIOD (PER)–expressing neurons. Two distinct oscillators have been functionally characterized under light-dark cycles. Lateral neurons (LNs) that express the pigment-dispersing factor (PDF) drive morning activity, whereas PDF-negative LNs are required for the evening activity. In constant darkness, several lines of evidence indicate that the LN morning oscillator (LN-MO) drives the activity rhythms, whereas the LN evening oscillator (LN-EO) does not. Since mutants devoid of functional CRYPTOCHROME (CRY), as opposed to wild-type flies, are rhythmic in constant light, we analyzed transgenic flies expressing PER or CRY in the LN-MO or LN-EO. We show that, under constant light conditions and reduced CRY function, the LN evening oscillator drives robust activity rhythms, whereas the LN morning oscillator does not. Remarkably, light acts by inhibiting the LN-MO behavioral output and activating the LN-EO behavioral output. Finally, we show that PDF signaling is not required for robust activity rhythms in constant light as opposed to its requirement in constant darkness, further supporting the minor contribution of the morning cells to the behavior in the presence of light. We therefore propose that day–night cycles alternatively activate behavioral outputs of the Drosophila evening and morning lateral neurons

Gènes d’horloge : de la drosophile à l’homme.

International audienceThe circadian clock that governs sleep-wake rhythms stems from a small set of genes, called clock genes, that are highly conserved during evolution. In insects as in mammals, a transcriptional feedback loop generates 24 h molecular oscillations. Two major transcriptional activators direct the expression of genes encoding repressors the accumulation of which leads a few hours later to transcriptional inhibition. This cyclic transcription is the core of the circadian oscillator and controls a large number of target genes (about 5 % of the genome), the nature of which varies from one organ to another depending on the physiology of the tissues. The period of the molecular oscillations relies on the accumulation rate of the repressors, their transfer into the cell nucleus, their ability to inhibit transcription, and their lifetime. These various parameters are largely based on post-translational regulations that depend on genes encoding kinases, phosphatases and ubiquitin ligases for a large fraction of them. Several syndromes that affect the sleep-wake rhythm were characterized in the human population. In particular, shifts of the sleep-wake rhythms compared to day-night cycles have been identified and associated with mutations in clock genes. These mutations disrupt not only the brain clock that governs sleep-wake rhythms but also the temporal organization of many physiological processes (metabolism, detoxification etc.) through the clocks that are present in the different cell types of the body.L’horloge circadienne qui gouverne les rythmes veille-sommeil repose sur une petite série de gènes communément appelés gènes d’horloge et fortement conservés au cours de l’évolution. Chez les insectes comme chez les mammifères, une boucle de rétroaction transcriptionnelle génère des oscillations moléculaires d’une période de 24h. Deux activateurs de transcription majeurs dirigent l’expression de gènes codant pour des répresseurs dont l’accumulation conduit quelques heures plus tard à l’inhibition de la transcription. Cette transcription cyclique est au cœur de l’oscillateur circadien et régule également un nombre important de gènes cibles (environ 5 % du génome), dont la nature varie d’un organe à l’autre en fonction de la physiologie des tissus considérés. La période de l’oscillation moléculaire dépend de la vitesse d’accumulation des répresseurs, de leur transfert dans le noyau de la cellule, de leurcapacité à inhiber la transcription et de leur durée de vie. Ces différents paramètres reposent en grande partie sur des régulations post-traductionnelles mises en œuvre par une batterie de gènes codant en particulier pour des kinases, phosphatases et ubiquitine ligases. Plusieurs syndromes affectant le rythme veille-sommeil ont été caractérisés dans la population humaine. En particulier, des décalages du rythme par rapport aux cycles jour-nuit ont été identifiés et associés à des mutations dans des gènes d’horloge. Ces mutations perturbent non seulement l’horloge cérébrale qui gouverne les rythmes veille-sommeil mais également l’organisation temporelle de nombreux processus physiologiques (métabolisme, détoxification etc.) au travers des horloges qui sont présentes dans les différents types cellulaires del’organisme