Project description:The cellular composition of the brain and how it is affected by starvation, remains largely unknown. Here we introduce a single-cell transcriptome atlas of the entire Drosophila melanogaster first instar larval brain. We first assigned cell type identity based on the expression of previously characterized marker genes, allowing us to distinguish five major groups: neural progenitors cells, differentiated neurons, glial cells, undifferentiated neurons as well as non-neural cells corresponding to organs and structures located adjacent to the brain. All major classes were further subdivided into multiple subtypes based on cluster analysis, revealing critical biological features of various cell types. Moreover, we included two different feeding conditions: normal fed versus starved. After starvation, the transcriptional profile of several cell clusters were altered, while the overall composition of the brain remains unaffected. Intriguingly, different cell clusters show very distinct responses to starvation, suggesting the presence of cell-specific programs for nutrition availability. Establishing a single-cell transcriptome atlas of the larval brain provides a powerful tool to explore cell diversity, assess genetic profiles of neurogenic, neuronal and glial cell types. The analysis of neurotransmitters, neuropeptides and their respective receptors may further open the doors for functional studies.
Project description:The diversity of cell types and regulatory states in the brain, and how these change during ageing, remains largely unknown. We present a single-cell transcriptome atlas of the entire adult Drosophila melanogaster brain sampled across its lifespan. Cell clustering identified 87 initial cell clusters that are further subclustered and validated by targeted cell-sorting. Our data shows high granularity and identifies a wide range of cell types. Gene network analyses using SCENIC revealed regulatory heterogeneity linked to energy consumption. During ageing, RNA content declines exponentially without affecting neuronal identity in old brains. This single-cell brain atlas covers nearly all cells in the normal brain and provides the tools to study cellular diversity alongside other Drosophila and mammalian single-cell datasets in our unique single-cell analysis platform. These results allow comprehensive exploration of all transcriptional states of an entire ageing brain.
Project description:Drosophila larval ventral nerve cord (VNC) shares many similarities with the spinal cord of vertebrates and has emerged as a major model for understanding the development and function of motor systems. We use high quality single cell RNA sequencing to create a comprehensive atlas of larval VNC cell types. Our atlas provides a high-resolution characterization of larval VNC capturing primary neurons, glia and the functional landscape that coordinates larval behavior. At the same time, this atlas offers unique insights into neurogenesis and into the strategies and signaling networks utilized for generation of the adult VNC.
Project description:Understanding cell type identity in complex tissues or organisms requires integration of each cell's expression profile with its spatial location within the tissue under study. We developed a high-throughput method that combines in vitro single-cell RNA-sequencing with a gene expression atlas to map single cells back to their location within the tissue of interest. We used the developing brain of a marine annelid, Platynereis dumerilii that is an important model system for studying bilaterian brain evolution, to benchmark our approach. To generate the single-cell mRNA-sequencing data, P. dumerilii larval brains were dissociated, followed by cell capture, cDNA synthesis and amplification on the C1 Single-Cell Auto Prep IFC for 10-17 um cells (Fluidigm). Sequencing libraries were produced using Nexera XT DNA kit (Illumina). In total, we sequenced 213 samples, of which 129 correspond to single, alive cells (as judged by visual inspection of the captured cells) with the remainder consisting of a variety of single dead cells (n=18), wells containing extracellular matrix contaminants (n=8) or multiple cells (n=17), as well as a negative controls where no cells were observed (n=41). For this dataset, we achieved ~90% success rate for the spatial mapping of the single-cell RNA-seq data to P. dumerilii brain atlas. NOTE: 72 additional samples were added on 13th December 2014.
Project description:Our study focuses on understanding the early transcriptional changes taking place during the divergence of the adult muscle precursors that give rise to indirect flight muscles and direct flight muscles in Drosophila. We analyzed the heterogenous cell population of the adult muscle precursors by scRNA-seq and build an integrated single-cell reference atlas. We addressed the differences among muscle-type and different cell state during myoblast differentiation. Also, our dataset includes the transcriptional profile of the epithelial cells localized in the presumptive hinge and notum of third instar larval wing discs. In addition we studied the functional relevance of Amalgam in flight muscle development by depleting Ama expression specifically in the adult muscle precursors. We determined the transcriptional changes and perturbations in AMP cell identity upon Ama knockdown.