Project description:Here we study the adult functions of the single Drosophila member of this subfamily, DHR78, with the goal of defining its ancestral functions in the absence of genetic redundancy. We show that DHR78 mutants have a shortened lifespan and reduced motility. Mated DHR78 mutant females display reduced triglycerides along with a reduced feeding rate. Transcriptional profiling reveals a major role for DHR78 in promoting the expression of genes that are abundantly expressed in the midgut, suggesting that it contributes to nutrient uptake. We also identify roles for DHR78 in maintaining the expression of genes in the ecdysone and Notch signaling pathways.
Project description:DHR96 is a Drosophila member of the CAR/PXR/LXR family of Nuclear receptors. To Identify potential target genes for the DHR96 nuclear receptor we used microarray analysis to identify genes that were mis-regulated relative to control animals in the DHR96 mutant. Experiment Overall Design: Total RNA was isolated from mature adult DHR96 mutant and genetically matched Canton S controls and subjected to affymetrix microarray analysis.
Project description:The vertebrate nuclear hormone receptor steroidogenic factor 1 (SF1; NR5A1) controls reproductive development and regulates the transcription of steroid-modifying cytochrome P450 genes. We find that the SF1-related Drosophila nuclear hormone receptor HR39 is also essential for sexual development. In Hr39 mutant females, the sperm-storing spermathecae and glandular parovaria are absent or defective, causing sterility. Our results indicate that spermathecae and parovaria secrete reproductive tract proteins required for sperm maturation and function, like the mammalian epididymis and female reproductive tract. Hr39 controls the expression of specific cytochrome P450 genes and is required in females both to activate spermathecal secretion and repress male-specific courtship genes such as takeout. Thus, a pathway that, in vertebrates, controls sex-specific steroid hormone production, also mediates reproductive functions in an invertebrate. Our findings suggest that Drosophila can be used to model more aspects of mammalian reproductive biology than previously believed. Experiment Overall Design: Wild type and Hr39(04443) Spermathecae, Wild type and Hr39(04443) Reproductive Tract
Project description:The vertebrate nuclear hormone receptor steroidogenic factor 1 (SF1; NR5A1) controls reproductive development and regulates the transcription of steroid-modifying cytochrome P450 genes. We find that the SF1-related Drosophila nuclear hormone receptor HR39 is also essential for sexual development. In Hr39 mutant females, the sperm-storing spermathecae and glandular parovaria are absent or defective, causing sterility. Our results indicate that spermathecae and parovaria secrete reproductive tract proteins required for sperm maturation and function, like the mammalian epididymis and female reproductive tract. Hr39 controls the expression of specific cytochrome P450 genes and is required in females both to activate spermathecal secretion and repress male-specific courtship genes such as takeout. Thus, a pathway that, in vertebrates, controls sex-specific steroid hormone production, also mediates reproductive functions in an invertebrate. Our findings suggest that Drosophila can be used to model more aspects of mammalian reproductive biology than previously believed. Keywords: mutant/wild-type comparison and tissue comparison
Project description:Here we show that the Drosophila nuclear receptor E78A regulates transcription in adult animals facilitating dietary lipid uptake. E78A mutant adults are viable with normal developmental timing, locomotor activity, female fecundity, but have significantly reduced stored triglycerides. This reduction in whole body triglyceride stores appears to originate from the midgut, using neutral lipid stainings we determined lipid levels in the midgut were greatly reduced. Upon examining our RNA-seq analysis we found that a gastric lipase, CG17192, is transcriptionally coordinated by E78A. CG17192 is expressed in an adult, intestinal specific fashion within control flies, and has a human ortholog. Through dietary supplementation and genetic testing we determined that the whole body hypolipidemia seen within E78A mutants is dependent on CG17192 expression within the intestine. Restoration of this lipase in the intestine of mutant flies is sufficient to restore normal lipid levels. Our data support the model that E78A contributes to a transcriptional regulation of the gastric lipase, CG17192, thus directing dietary triglyceride uptake in the adult fly.
Project description:T cell antigen receptor (TCR) signaling triggers selective cytokine expression to drive T cell proliferation and differentiation required for immune defense and surveillance. The nuclear signaling events responsible for specificity in cytokine gene expression upon T cell activation are largely unknown. Here, we uncover formation of a dynamic actin filament network in the nucleus that regulates cytokine expression for effector functions of CD4 T lymphocytes. TCR engagement triggers the rapid and transient formation of a nuclear actin filament network via nuclear Arp2/3 complex, induced by elevated nuclear Ca2+ levels and regulated via N-Wasp and NIK. Specific interference with TCR-induced formation of nuclear actin filaments impairs production of effector cytokines and prevents generation of antigen-specific antibodies, but does not interfere with immune synapse formation and cell proliferation. Ca2+-regulated actin polymerization in the nucleus allows CD4 T cells the rapid conversion of TCR signals into effector functions required for T cell help Identification of nuclear F-actin sensitive genes upon TCR signaling