Project description:Analysis of differential gene expression in third instar Drosophila salivary glands in the absence versus presence of cohesin. ABSTRACT: Developmental abnormalities observed in Cornelia de Lange Syndrome (CdLS) have been genetically linked to mutations in the cohesin machinery. These findings raise the possibility that cohesin, in addition to its canonical function of mediating sister chromatid cohesion, might also be involved in regulating gene expression. We report that cleavage of cohesinM-CM-^Us kleisin subunit in post-mitotic Drosophila salivary glands induces major changes (both up and down) in the transcript levels of many genes. Kinetic analyses of changes in transcript levels upon cohesin cleavage reveal that a subset of genes responds to cohesin cleavage within a few hours. In addition, cohesin binds to most of these loci, suggesting that cohesin is directly regulating their expression. Amongst these genes are several that are regulated by the steroid hormone Ecdysone. Transcripts at EcR and Eip74EF, which encode an Ecdysone Receptor and an Ecdysone-regulated transcription factor, respectively, decline ten-fold within four hours of cohesin cleavage. Cytological visualization of transcription at selected Ecdysone-responsive genes reveals that puffing at Eip74EF ceases within an hour or two of cohesin cleavage, long before any decline in EcR associated with this locus. We conclude that cohesin regulates expression of a distinct set of genes, including those mediating the Ecdysone response. A heat-inducible transgene (hs-TEV) was used to induce TEV in terminally differentiated third instar Drosophila salivary glands expressing either wild type (+ cohesin) or TEV-cleavable myc10-tagged Rad21 protein (Rad21TEV, - cohesin). Total RNA was isolated from + and - cohesin salivary glands 10-12 hours after heat shock induction of TEV (7 independent biological samples each). RNA samples were converted to cDNA, labeled with Cy3 and Cy5 respectively (3x) and vice versa (4x; dye swaps), and hybridized to INDAC FL003 arrays. Analysis of seven arrays, each hybridized to an independently generated sample-pair revealed major differences in transcript levels between + and - cohesin samples.
Project description:Analysis of differential gene expression in third instar Drosophila salivary glands in the absence versus presence of cohesin. ABSTRACT: Developmental abnormalities observed in Cornelia de Lange Syndrome (CdLS) have been genetically linked to mutations in the cohesin machinery. These findings raise the possibility that cohesin, in addition to its canonical function of mediating sister chromatid cohesion, might also be involved in regulating gene expression. We report that cleavage of cohesinÕs kleisin subunit in post-mitotic Drosophila salivary glands induces major changes (both up and down) in the transcript levels of many genes. Kinetic analyses of changes in transcript levels upon cohesin cleavage reveal that a subset of genes responds to cohesin cleavage within a few hours. In addition, cohesin binds to most of these loci, suggesting that cohesin is directly regulating their expression. Amongst these genes are several that are regulated by the steroid hormone Ecdysone. Transcripts at EcR and Eip74EF, which encode an Ecdysone Receptor and an Ecdysone-regulated transcription factor, respectively, decline ten-fold within four hours of cohesin cleavage. Cytological visualization of transcription at selected Ecdysone-responsive genes reveals that puffing at Eip74EF ceases within an hour or two of cohesin cleavage, long before any decline in EcR associated with this locus. We conclude that cohesin regulates expression of a distinct set of genes, including those mediating the Ecdysone response.
Project description:Developmental abnormalities observed in Cornelia de Lange Syndrome (CdLS) have been genetically linked to mutations in the cohesin machinery. These findings raise the possibility that cohesin, in addition to its canonical function of mediating sister chromatid cohesion, might also be involved in regulating gene expression. We report that cleavage of cohesin’s kleisin subunit in post-mitotic Drosophila salivary glands induces major changes (both up and down) in the transcript levels of many genes. Kinetic analyses of changes in transcript levels upon cohesin cleavage reveal that a subset of genes responds to cohesin cleavage within a few hours. In addition, cohesin binds to most of these loci, suggesting that cohesin is directly regulating their expression. Amongst these genes are several that are regulated by the steroid hormone Ecdysone. Transcripts at EcR and Eip74EF, which encode an Ecdysone Receptor and an Ecdysone-regulated transcription factor, respectively, decline ten-fold within four hours of cohesin cleavage. Cytological visualization of transcription at selected Ecdysone-responsive genes reveals that puffing at Eip74EF ceases within an hour or two of cohesin cleavage, long before any decline in EcR associated with this locus. We conclude that cohesin regulates expression of a distinct set of genes, including those mediating the Ecdysone response DamID experiments for Rad21 were performed on gDNA from drosophila salivary glands. Samples were hybridized to 380k NimbleGen arrays with 300 bp probe spacing. The experiment was done in duplicate in the reverse dye orientation.
Project description:In spite of the many recent developments in the field of vector sialomics, the salivary glands of larvalmosquitoes have been largely unexplored. We used whole-transcriptome microarray analysis to create a gene-expression profile of the salivary gland tissue of fourth-instar Anopheles gambiae larvae, and compare it to the gene-expression profile of a matching group of whole larvae. We identified a total of 221 probes with expression values that were (a) significantly enriched in the salivary glands, and (b)sufficiently annotated as to allow the prediction of the presence/absence of signal peptides in their corresponding gene products. Based on available annotation of the protein sequences associated with these probes, we propose that the main roles of larval salivary secretions include: (a) immune response, (b) mouthpart lubrication, (c) nutrient metabolism, and (d) xenobiotic detoxification. Other highlights of the study include the cloning of a transcript encoding a previously unknown salivary defensin (AgDef5), the confirmation of mucus secretion by the larval salivary glands, and the first report of salivary lipocalins in the Culicidae. Keywords: Anopheles gambiae, salivary gland, Diptera, gene expression, salivary defensin, transcriptome, salivary lipocalin
Project description:When misexpressed in late Drosophila prepupae, the transcription factor Senseless (Sens) blocks death of the larval salivary glands that normally occurs in the early pupa. The aim of the experiment was to identify genes responding to Sens that might mediate the effect of the protein on cell death and other biological processes. The yeast transcription factor GAL4, expressed from a heat-inducible transgene (P{GAL4-Hsp70.PB}89-2-1), was used to drive expression of Sens from a UAS-sens transgene. After crossing the GAL4 and UAS lines, expression of GAL4 was induced by a 30-min heat shock treatment (37 °C) of the progeny at 9 hours after puparium formation. Salivary glands were dissected at 14 hours after puparium formation and RNA isolated for microarray analysis with Affymetrix GeneChips. Control samples were obtained from animals treated the same way carrying one copy of the GAL4 transgene (progeny of a cross between flies of the P{GAL4-Hsp70.PB}89-2-1 and w1118 strains) and w1118 animals. The microarray data identified several genes associated with programmed cell death, including caspase genes, which respond to Sens. In addition, the data show that many Drosophila genes respond to the yeast transcription factor GAL4 in a UAS-independent manner. To identify target genes of Sens that are of biological relevance, gene expression patterns in the presence of Sens were compared to gene expression patterns in both the presence and the absence of GAL4. This comparison revealed that Sens seems to preferentially downregulate targets that are upregulated by GAL4, suggesting that these genes may not necessarily constitute true transcriptional targets of Sens. Experiment Overall Design: Experimental RNA samples were obtained in 3 biological replicates from sens-expressing salivary glands (SG_sens_14APF_rep1, SG_sens_14APF_rep2, SG_sens_14APF_rep3) and compared to control samples obtained from GAL4-expressing salivary glands (SG_1P{hsGAL4}89(S)_14APF_rep1) and non-GAL4-expressing salivary glands (SG_w1118_14APF_rep1, SG_w1118_14APF_rep2). All samples were compared using dChip and normalized to the same baseline array (median intensity 150).
Project description:This SuperSeries is composed of the following subset Series: GSE31895: ChIP with anti-orc2 antibody to identify regions of orc binding in third instar salivary glands of WT and SuUR mutant Drosophila GSE31896: RNAPolII ChIP to find differences between third instar salivary glands of WT and SuUR GSE31897: ChIP with anti-H3K27me3 to compare binding in salivary glands of WT and SuUR Drosophila GSE31898: CGH to ascertain levels of gDNA in third instar salivary glands of various mutant Drosophila GSE31899: ChIP-Seq of ORC2 bound to third instar salivary gland DNA in WT and mutant Drosophila, analyzed by Illumina sequencing GSE33017: Expression profile of third instar larval salivary gland tissue Refer to individual Series
Project description:Comparative genomic hybridization was performed to compare levels of gDNA in third instar salivary glands of Drosophila mutants/nulls in the SuUR and orc proteins, compared with 0-2hr diploid embryo gDNA. This illustrates regions of differential replication in the genome. CGH of salivary gland DNA compared with diploid early embryonic samples for four different Drosophila strains
Project description:Expression profiling of NSL3, MCRS2 and MBDR2 RNAi-mediated depletion in Drosophila salivary glands. This experiment is related to experiment E-MTAB-214