Project description:It consists of Chip-chip data for H3K4, PolII (4h8), H3K36, H3K9me3 and HP1 from 10 and 40 day old female Drosophila melanogaster (Canton S), as well as expression array data taken from the same time points. This SuperSeries is composed of the SubSeries listed below.
Project description:The w1118 strain is an inbred lab stock widely used in genetic and transgenic studies. w1118 males have a median life span of 35 days. Adult males were collected within 24 hr after eclosion. Approximately 200 flies were maintained in constant darkness in each food bottle at 25°C and 70% humidity and were transferred to fresh bottles every 3-4 days. Transcripts were harvested at d3 and d47. To separate the head from the rest of the body, flies were frozen and briefly vortexed in liquid nitrogen. Fly heads were collected using a sieve which retained fly bodies. Total RNA was extracted using Trizol (GIBCO/BRL). Poly(A) RNA was isolated using Oligotex resin (Qiagen). Samples were profiled with Affymetrix DrosGenome1 GeneChips, using standard Affymetrix protocol. Keywords: time-course
Project description:This SuperSeries is composed of the following subset Series:; GSE826: Aging in heads from adult Drosophila males, w118 strain; GSE827: Oxidative stess in Drosophila heads Experiment Overall Design: Refer to individual Series
Project description:Chromatin structure affects the accessibility of DNA to transcription, repair, and replication. Changes in chromatin structure occur during development, but less is known about changes during aging. We examined the state of chromatin structure and its effect on gene expression during aging in Drosophila at the whole genome and cellular level using whole-genome tiling microarrays of activation and repressive chromatin marks, whole-genome transcriptional microarrays and single-cell immunohistochemistry. We found dramatic reorganization of chromosomal regions with age. Mapping of H3K9me3 and HP1 signals to fly chromosomes reveals in young flies the expected high enrichment in the pericentric regions, the 4th chromosome, and islands of facultative heterochromatin dispersed throughout the genome. With age, there is a striking reduction in this enrichment resulting in a nearly equivalent level of H3K9me3 and HP1 in the pericentric regions, the 4th chromosome, facultative heterochromatin, and euchromatin. These extensive changes in repressive chromatin marks are associated with alterations in age-related gene expression. Large-scale changes in repressive marks with age are further substantiated by single-cell immunohistochemistry that shows changes in nuclear distribution of H3K9me3 and HP1 marks with age. Such epigenetic changes are expected to directly or indirectly impinge upon important cellular functions such as gene expression, DNA repair, and DNA replication. The combination of genome-wide approaches such as whole-genome chromatin immunoprecipitation and transcriptional studies in conjunction with single-cell immunohistochemistry as shown here provide a first step toward defining how changes in chromatin may contribute to the process of aging in metazoans.
Project description:The piRNA pathway controls transposon expression in animal germ cells, thereby ensuring genome stability over generations. piRNAs are maternally deposited and required for proper transposon silencing in adult offspring. However, a long-standing question in the field is the precise function of maternally deposited piRNAs and its associated factors during embryogenesis. Here, we probe the spatio-temporal expression patterns of several piRNA pathway components during early stages of development. Amongst those, factors required for transcriptional gene silencing (TGS) showed ubiquitous abundance in somatic and pole cells throughout the first half of embryogenesis. We further analysed the transcriptomes of various embryo stages and correlated these with the presence of selected chromatin marks. We found that a number of transposon families show bursts of transcription during early embryonic stages. Transposons heavily targeted by maternally deposited piRNAs accumulated repressive chromatin marks following their spike in expression. Furthermore, depletion of maternally deposited Piwi protein in early embryos resulted in increased expression of transposons targeted by inherited piRNAs and was accompanied by a strong loss of repressive chromatin marks at coding sequences. Overall, our data suggests a pivotal role for the piRNA pathway in transposon defence during Drosophila embryogenesis in somatic cells.
Project description:We used long-oligonucleotide microarrays to investigate whether alternative splicing in Drosophila is regulated in a sex-, stage-, or tissue-specific manner. To examine sex-specific splicing, we compared gene expression profiles of male and female pupae 12 hours after pupariation. To examine stage-specific splicing, we compared expression profiles of mixed-sex, 0-24 hour old embryos and mixed-sex, 12 hour old pupae. To examine tissue-specific splicing, we compared expression profiles of adult male heads and abdomens 24-48 hours after eclosion. To examine tissue-specific splicing, we compared expression profiles of adult male heads and abdomens at 24-48 hours after eclosion. Keywords: tissue-specific expression profiles
Project description:We used long-oligonucleotide microarrays to investigate whether alternative splicing in Drosophila is regulated in a sex-, stage-, or tissue-specific manner. To examine sex-specific splicing, we compared gene expression profiles of male and female pupae 12 hours after pupariation. To examine stage-specific splicing, we compared expression profiles of mixed-sex, 0-24 hour old embryos and mixed-sex, 12 hour old pupae. To examine tissue-specific splicing, we compared expression profiles of adult male heads and abdomens 24-48 hours after eclosion. To examine tissue-specific splicing, we compared expression profiles of adult male heads and abdomens at 24-48 hours after eclosion. Keywords: tissue-specific expression profiles Drosophila isogenic line WI89 was used. Mixed-sex, mixed-stage embryos were harvested from plates on which females had been allowed to oviposit for 24 hours. To obtain synchronized cohorts of pupae, male and female white prepupae were collected at 0-1 hour after pupariation and aged for 12 hours at 25C. Mixed-sex pupal samples were generated by mixing equal amount of male and female pupal RNA. Adult heads and abdomens were dissected from 24-48 hour old males. mRNA was isolated and labeled without amplification.