Neuroendocrine (NE) cells use large dense core vesicles (LDCVs) to traffic, process, store and secrete neuropeptide hormones through the regulated secretory pathway. The DIMM basic helix-loop-helix transcription factor of Drosophila controls the level of regulated secretory activity in NE cells. To pursue its mechanisms, we have performed two independent genome-wide analyses of DIMM's activities: (i) in vivo chromatin immunoprecipitation (ChIP) to define genomic sites of DIMM occupancy and (ii) deep sequencing of purified DIMM neurons to characterize their transcriptional profile. By this combined approach, we showed that DIMM binds to conserved E-boxes in enhancers of 212 genes whose expression is enriched in DIMM-expressing NE cells. DIMM binds preferentially to certain E-boxes within first introns of specific gene isoforms. Statistical machine learning revealed that flanking regions of putative DIMM binding sites contribute to its DNA binding specificity. DIMM's transcriptional repertoire features at least 20 LDCV constituents. In addition, DIMM notably targets the pro-secretory transcription factor, CREB-A, but significantly, DIMM does not target any neuropeptide genes. DIMM therefore prescribes the scale of secretory activity in NE neurons, by a systematic control of the regulated secretory pathway at steps that are both proximal and distal.
Genome-wide features of neuroendocrine regulation in Drosophila by the basic helix-loop-helix transcription factor DIMMED.
Sex, Specimen part
View SamplesTo amass candidate DIMM targets in addition to Phm (Park et al., 2008a), we used genome-wide microarray profiling by over-expressing DIMM throughout the embryonic nervous system. We compared profiles from experimental (elav>dimm) and control (elav-GAL4) embryos at 22-26 hr and 28-32 hr after egg laying (AEL). The design was intended to identify transcripts consistently up-regulated shortly after the induction of DIMM; in so doing, we could circumvent the lethality that ensues in late embryonic, and/ or by early larval stages, due to pan-neuronal DIMM expression.
Molecular organization of Drosophila neuroendocrine cells by Dimmed.
Specimen part
View SamplesDespite timely and successful surgery, 32% of patients with bilateral and 10% with unilateral cryptorchidism will develop azoospermia. Cryptorchid boys at risk of azoospermia display a typical testicular histology of impaired mini-puberty at the time of the orchidopexy.
Testicular gene expression in cryptorchid boys at risk of azoospermia.
Specimen part
View SamplesIt is well appreciated that reactive oxygen species (ROS) are deleterious to mammals, including humans, especially when generated in abnormally large quantities from cellular metabolism. Whereas the mechanisms leading to the production of ROS are rather well delineated, the mechanisms underlying tissue susceptibility or tolerance to oxidant stress remain elusive. Through an experimental selection over many generations, we have previously generated Drosophila melanogaster flies that tolerate tremendous oxidant stress and have shown that the family of antimicrobial peptides (AMP) is over-represented in these tolerant flies. Furthermore, we have also demonstrated that overexpression of even one AMP at a time (e.g. Diptericin) allows wild type flies to survive much better in hyperoxia. In the current study, we used a number of experimental approaches to investigate the potential mechanisms underlying hyperoxia tolerance in flies with antimicrobial peptide overexpression. We demonstrate that flies with Diptericin overexpression resist oxidative stress by increasing antioxidant enzyme activities and preventing an increase in ROS level after hyperoxia. Depleting the GSH pool using buthionine sulfoximine limits fly survival, thus confirming that enhanced survival observed in these flies is related to improved redox homeostasis. We conclude that a) AMPs play an important role in tolerance to oxidant stress; b) overexpression of Diptericin changes the cellular redox balance between oxidant and antioxidant, and c) this change in redox balance plays an important role in survival in hyperoxia.
Antimicrobial peptides increase tolerance to oxidant stress in Drosophila melanogaster.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Impact of brief exercise on circulating monocyte gene and microRNA expression: implications for atherosclerotic vascular disease.
Sex, Specimen part, Time
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Impact of brief exercise on peripheral blood NK cell gene and microRNA expression in young adults.
Sex, Specimen part
View SamplesPurpose: Avian photoreceptors are a diverse class of neurons, comprised of four single cones, the two members of the double cone, and rods. Many distinctive features of photoreceptor subtypes, including spectral tuning, oil droplet size and pigmentation, synaptic targets and spatial patterning, have been well characterized, but the molecular mechanisms underlying these attributes have not been explored. Furthermore, the signaling events and transcriptional regulators driving the differentiation of these diverse photoreceptors are currently unknown. Methods: To identify genes specifically expressed in distinct chicken (Gallus gallus) photoreceptor subtypes, we developed fluorescent reporters that label photoreceptor subpopulations, isolated these subpopulations using fluorescence-activated cell sorting, subjected them to next-generation sequencing, and conducted differential expression analysis. Results: We identified hundreds of differentially expressed genes from photoreceptor subpopulations labeled with rhodopsin, red opsin, green opsin, and violet opsin reporters. These genes are involved in a variety of processes, including phototransduction, transcriptional regulation, cell adhesion, maintenance of intra- and extra-cellular structure, and metabolism. Of particular note are a variety of differentially expressed transcription factors, which may drive and maintain photoreceptor diversity, and cell adhesion molecules that may mediate spatial patterning of photoreceptors and act to establish retinal circuitry. Conclusions: These analyses provide a framework for future studies that will dissect the role of these various factors in the differentiation of avian photoreceptor subtypes. Overall design: mRNA expression profiling of 5 pairs of photoreceptor subtypes isolated from chicken retinal explants, 3 replicates per sample
Transcriptome profiling of developing photoreceptor subtypes reveals candidate genes involved in avian photoreceptor diversification.
Specimen part, Subject
View SamplesWe tested the hypothesis on the mechanisms responsible for the early control of NK cell function by identifying a discrete set of genes in circulating NK cells that were altered by exercise.
Impact of brief exercise on peripheral blood NK cell gene and microRNA expression in young adults.
Sex, Specimen part
View SamplesWe tested the hypothesis on the mechanisms responsible for the early control of monocytes function by identifying a discrete set of genes in circulating monocytes that were altered by exercise.
Impact of brief exercise on circulating monocyte gene and microRNA expression: implications for atherosclerotic vascular disease.
Sex, Specimen part, Time
View SamplesOne of the critical substances that mammals highly regulate via the respiratory, cardiovascular and neurologic systems is O2. Both low and high O2 levels can induce major morbidities as well as mortality. Indeed, O2 has been often considered as both an elixir and a poison in humans. In current study, we have used an experimental selection approach to generate Drosophila strains that are tolerant to severe hyperoxic environment. Gene expression profiling is then applied to investigate the mechanisms underlying hyperoxia tolerance in the newly generated strains.
Experimental selection for Drosophila survival in extremely high O2 environments.
Specimen part
View Samples