Project description:A challenge in systems biology is to understand the gene regulatory networks that connect early cellular specification to terminal differentiation of specific cell types. In neurogenesis, neural specification has been well studied, but the link between the proneural transcriptional regulators of specification and the genes that must be activated to construct differentiated neurons is obscure. High resolution temporal profiling of gene expression reveals the events downstream of Atonal (Ato) proneural gene function in Drosophila sensory neurons. Unexpectedly, many differentiation genes are activated soon after specification, even before cell cycle exit and overt neuronal differentiation. Prominent among them are genes required for construction of the ciliary dendrite. Ato activates differentiation both directly and indirectly via several intermediate transcriptional regulators, including Rfx and a new Forkhead family factor. Our analysis of these factors and their regulation provides insight into how proneural factors regulate neuronal subtype differentiation. Investigating the molecular mechanisms of peripheral nervous sytem development in Drosophila melanogaster. Affymetrix Drosophila version 2.0 chips used to measure gene expression from GFP+ and GFP- cells from embryos expressing GFP under the control of the atonal gene enhancer in both wild type and mutant embryos. Data generated for three developmental time-points in quadruplicate.
Project description:A challenge in systems biology is to understand the gene regulatory networks that connect early cellular specification to terminal differentiation of specific cell types. In neurogenesis, neural specification has been well studied, but the link between the proneural transcriptional regulators of specification and the genes that must be activated to construct differentiated neurons is obscure. High resolution temporal profiling of gene expression reveals the events downstream of Atonal (Ato) proneural gene function in Drosophila sensory neurons. Unexpectedly, many differentiation genes are activated soon after specification, even before cell cycle exit and overt neuronal differentiation. Prominent among them are genes required for construction of the ciliary dendrite. Ato activates differentiation both directly and indirectly via several intermediate transcriptional regulators, including Rfx and a new Forkhead family factor. Our analysis of these factors and their regulation provides insight into how proneural factors regulate neuronal subtype differentiation. Investigating the molecular mechanisms of peripheral nervous sytem development in Drosophila melanogaster.
Project description:<p>Chronic sleep loss profoundly impacts metabolic health and shortens lifespan, but studies of the mechanisms involved have focused largely on acute sleep deprivation. To identify metabolic consequences of chronically reduced sleep, we conducted unbiased metabolomics on heads of three adult Drosophila short-sleeping mutants with very different mechanisms of sleep loss: fumin (fmn), redeye (rye), and sleepless (sss). Common features included elevated ornithine and polyamines, with lipid, acyl-carnitine, and TCA cycle changes suggesting mitochondrial dysfunction. Studies of excretion demonstrate inefficient nitrogen elimination in adult sleep mutants, likely contributing to their polyamine accumulation. Increasing levels of polyamines, particularly putrescine, promote sleep in control flies but poison sleep mutants. This parallels the broadly enhanced toxicity of high dietary nitrogen load from protein in chronically sleep-restricted Drosophila, including both sleep mutants and flies with hyper-activated wake-promoting neurons. Together, our results implicate nitrogen stress as a novel mechanism linking chronic sleep loss to adverse health outcomes-and perhaps for linking food and sleep homeostasis at the cellular level in healthy organisms.</p>
Project description:This project’s aim was to compare the transcriptional profiles of olfactory sensory neurons in Drosophila melanogaster in order to identify novel genes that specify neuron-specific functions/phenotypes or may otherwise be involved in the development of the olfactory system. The isolation of sufficient numbers of intact olfactory sensory neurons (OSN) from the antenna of Drosophila melanogaster has so far limited single-cell transcriptomic approaches being applied to the adult fly antenna. Targeted DamID (TaDa) provides an alternative approach for profiling transcriptional activity in a cell-specific manor that bypasses the need for isolating OSN. Using the Gal4/UAS system, we applied TaDa to seven OSN populations and compared differences in Pol II occupancy for genes across these datasets.
Project description:While microRNAs (miRNAs) have recently emerged as critical post-transcriptional modulators of gene expression in neuronal development, very little is known regarding the roles of miRNA-mediated regulation in the specification of cell-type specific dendritic complexity. The dendritic arborization (da) sensory neurons of the Drosophila PNS offer an excellent model system for elucidating the molecular mechanisms governing class specific dendrite morphogenesis and for exploring miRNA-mediated control of this process. To facilitate functional analyses of miRNA regulation in da neurons, we have conducted whole-genome miRNA expression profiling as well as mRNA expression profiling of three distinct classes of da neurons, thereby generating a comprehensive molecular gene expression signature within these individual subclasses of da neurons. To further validate the role of these expressed miRNAs in directing dendritic architecture, we conducted a genome-wide UAS-miRNA phenotypic screen using live-image confocal microscopy followed by semi-automated neurometric quantification, to directly assess the effect of over/mis-expression of individual and clustered miRNAs on neurons of varying dendritic complexity. Through this approach, we have identified numerous miRNAs with previously unknown functions in dendritic development. Gain-of-function and loss-of-function analyses revealed an endogenous role miR-2b and miR-13b (members of the K-box family) and miR-12/283/304 in dendritic patterning in da neuron subclasses. Moreover, using an integrative bioinformatic analysis approach involving inverse correlation between miRNA and mRNA expression profiling data in combination with existing target prediction algorithms, we have identified putative target of these miRNAs in regulating da neuron dendritic development. Validation of these predicted miRNA-target relationships via phenotypic analyses as well as QPCR, revealed the regulatory effect of these molecules in restricting dendritic branching in da neurons.