The discovery of direct downstream targets of transcription factors (TFs) is necessary for understanding the genetic mechanisms underlying complex, highly regulated processes such as development. In this report, we have used a combinatorial strategy to conduct a genome-wide search for novel direct targets of Eyeless (Ey), a key transcription factor controlling early eye development in Drosophila. Like many other TFs, little is known for Ey direct downstream targets. To date, only one gene, sine oculis (so), has been identified as Ey direct targets in Drosophila. Therefore, it is crucial to identify additional targets in order to gain a better understanding of ey function. To overcome the lack of high quality consensus binding site sequences, phylogenetic shadowing of Ey binding sites in so was used to construct a position weight matrix (PWM) of the Ey protein. This PWM was then used for in silico prediction of potential binding sites in the Drosophila melanogaster genome. To reduce the false positive rate, conservation of these potential binding sites was assessed by comparing the genomic sequences from seven Drosophila species. In parallel, microarray analysis of wild-type versus ectopic ey-expressing tissue, followed by microarray-based epistasis experiments in an atonal (ato) mutant background, identified 188 genes induced by ey. Intersection of in silico predicted conserved Ey binding sites with the candidate gene list produced through expression profiling yields a list of 20 putative ey-induced, eye-enriched, ato-independent, direct targets of Ey, including so. The accuracy of this list of genes was confirmed using both in vitro and in vivo methods. Initial analysis reveals three genes, eyes absent, shifted, and Optix, as novel direct targets of Ey. These results suggest that the integrated strategy of computational biology, genomics, and genetics is a powerful approach that can be applied to systematically identify direct downstream targets for any transcription factor genome-wide.
Genome-wide identification of direct targets of the Drosophila retinal determination protein Eyeless.
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View SamplesThe alveolar type 1 (AT1) cell covers >95% of the gas exchange surface and is extremely thin to facilitate passive gas diffusion. The development of this highly specialized cell is poorly understood including fundamental questions regarding cell number and morphology. Using new molecular stereology and single cell imaging methods, we show that AT1 cells develop via a non-proliferative two-step process while maintaining proliferative potential. In the flattening step, AT1 cells remodel cell junctions and undergo molecular specification. In the folding step, AT1 cells are sculptured to match secondary septa formation, resulting in a single AT1 cell spanning multiple alveoli. AT1 cells grow in size by >10-fold, fueling most of the postnatal lung growth. Strikingly AT1 cells proliferate upon ectopic SOX2 expression and undergo stage-dependent cell fate reprogramming. These results contradict the traditional view of AT1 cells being terminally differentiated and provide insights to alveolar maturation. In this experiment, we conducted next-generation sequencing on flow-sorter AT1 cells isolated from mouse lungs ectopically expressing Sox2 under the control of the AT1-specific promoter Scnn1a versus control AT1 cells. Overall design: Two samples of Sox2-expressing AT1 cells versus two control AT1 samples.
The development and plasticity of alveolar type 1 cells.
Cell line, Subject
View SamplesWe performed RNA-seq on human embryonic stem cells raised in an established condition to produce 95% Nkx2.1 cells, with and without withdrawal of Wnt-agonist CHIR99021 or addition of Wnt-inhibitor IWP2 Overall design: Human lung progenitors were derived from RUES2 as described in Huang et al 2014, Huang et al 2015. Wnt agonist withdrawal or addition of Wnt inhibitor was done at day 12, with cell harvest for RNA-seq at day 12 (control) and day 15 (control and treatment)
β-Catenin maintains lung epithelial progenitors after lung specification.
Specimen part, Treatment, Subject, Time
View SamplesWe investigated the molecular mechanisms of chronic alcohol consumption or lipopolysaccharide insult by gene expression profiling in prefrontal cortex and liver of C57BL/6J mice.
Gene expression in brain and liver produced by three different regimens of alcohol consumption in mice: comparison with immune activation.
Age, Specimen part
View SamplesProduction of functional proteins requires multiple steps including gene transcription and post-translational processing. MicroRNAs (miRNA) can regulate individual stages of these processes. Despite the importance of the cystic fibrosis transmembrane conductance regulator (CFTR) channel for epithelial anion transport, how its expression is regulated remains uncertain. We discovered that microRNA-138 regulates CFTR expression through its interactions with the transcriptional regulatory protein SIN3A. Treating airway epithelia with a miR-138 mimic increased CFTR mRNA and also enhanced CFTR abundance and transepithelial Cl- permeability independently of elevated mRNA levels. A miR-138 anti-miR had the opposite effects. Importantly, miR-138 altered the expression of many genes encoding proteins that associate with CFTR and may influence its biosynthesis. The most common CFTR mutation, F508, causes protein misfolding, degradation, and cystic fibrosis. Remarkably, manipulating the miR-138 regulatory network also improved biosynthesis of CFTR-F508 and restored Cl- transport to cystic fibrosis airway epithelia. This novel miRNA-regulated network directs gene expression from the chromosome to the cell membrane, indicating that an individual miRNA can control a cellular process broader than previously recognized. This discovery also provides new therapeutic avenues for restoring CFTR function to cells affected by the most common cystic fibrosis mutation.
A microRNA network regulates expression and biosynthesis of wild-type and DeltaF508 mutant cystic fibrosis transmembrane conductance regulator.
Specimen part, Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
A high protein diet during pregnancy affects hepatic gene expression of energy sensing pathways along ontogenesis in a porcine model.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Transcriptional response of skeletal muscle to a low-protein gestation diet in porcine offspring accumulates in growth- and cell cycle-regulating pathways.
Specimen part
View SamplesGerman landrace gilts were fed a high protein diet (HP, 30% CP) throughout their whole pregnancy. Subsequently hepatic transcriptome profiles of the offspring were analysed at prenatal (94 dpc) and postnatal stages (1, 28, 188 dpn)
A high protein diet during pregnancy affects hepatic gene expression of energy sensing pathways along ontogenesis in a porcine model.
Specimen part
View SamplesGerman landrace gilts were fed an adequate protein diet (AP, 12% CP) throughout their whole pregnancy. Subsequently hepatic transcriptome profiles of the offspring were analysed at prenatal (94 dpc) and postnatal stages (1, 28, 188 dpn).
A high protein diet during pregnancy affects hepatic gene expression of energy sensing pathways along ontogenesis in a porcine model.
Specimen part
View SamplesGerman landrace gilts were fed a high protein diet (HP, 30% CP) throughout their whole pregnancy. Subsequently muscle transcriptome profiles of the offspring were analysed at prenatal (94 dpc) and postnatal stages (1, 28, 188 dpn)
Transcriptional response of skeletal muscle to a low-protein gestation diet in porcine offspring accumulates in growth- and cell cycle-regulating pathways.
Specimen part
View Samples