Project description:We sequenced mRNA from blastoderm embryos of Drosophila melanogaster, Drosophila yakuba, Drosophila pseudoobscura and Drosophila virilis. Two samples contain pooled mRNA from several species, and the remaining 24 samples contain mRNA from a single species. Methods: Retinal mRNA profiles of Blastoderm embryos
Project description:We sequenced mRNA from blastoderm embryos of Drosophila melanogaster, Drosophila yakuba, Drosophila pseudoobscura and Drosophila virilis. Two samples contain pooled mRNA from several species, and the remaining 24 samples contain mRNA from a single species. Methods: Retinal mRNA profiles of Blastoderm embryos Comparison of the evolution of gene expression and regulatory TF binding in early Drosophila embryos.
Project description:We report the analysis of the transcriptome in Drosophila embryos with two genotypes (1: wild type, 2: embryos from germline clones of a SHMT mutant (allele X238)) and two developmental stages (1: pre-blastoderm, stage 1 and stage 2, 0–1h after egg lay, 2: late blastoderm/cellularisation stage 5, 1.5–2.5 h after egg lay)
Project description:We sequenced mRNA from transverse slices of embryos from a variety of D. melanogaster mutants (bicoid over-expression, bicoid knockdown, hunchback knocdown, and zelda mutant) at the blastoderm stage to determine genome-wide patterns of gene expression.
Project description:As the Drosophila embryo transitions from the use of maternal RNAs to zygotic transcription, domains of “open” chromatin, with relatively low nucleosome density and specific histone marks, are established at promoters and enhancers involved in patterned embryonic transcription. However it remains unclear whether open chromatin is a product of activity - transcription at promoters and patterning transcription factor binding at enhancers - or whether it is established by independent mechanisms. Recent work has implicated the ubiquitously expressed maternal factor Zelda in this process. To assess the relative contribution of activity in the establishment of open chromatin , we have probed chromatin accessibility across the anterior-posterior axis of early Drosophila melanogaster embryos by applying a transposon based assay for chromatin accessibility (ATAC-seq) to anterior and posterior halves of hand-dissected, cellular blastoderm embryos. We find that genome-wide chromatin accessibility is remarkably similar between the two halves. Promoters and enhancers that are active in exclusively one half of the embryo have open chromatin in the other half, demonstrating that chromatin accessibility is not a direct result of activity. However there is a small skew at enhancers that drive transcription exclusively in either the anterior or posterior half of the embryo, with greater accessibility in the region of activity. Taken together these data support a model in which regions of chromatin accessibility are defined and established by ubiquitous factors, and fine tuned subsequently by activity.
Project description:We sequenced mRNA from transverse slices of embryos from a variety of D. melanogaster mutants (bicoid over-expression, bicoid knockdown, hunchback knocdown, and zelda mutant) at the blastoderm stage to determine genome-wide patterns of gene expression. mRNA from transverse sections of single D. melanogaster embryos mutant for patterning TFs was sequenced.
Project description:Purpose: The goal of this study was to measure how chromatin accessibility and nucleosome positioning changes as embryos undergo the midblastula transition (MBT). Methods: Single or paired embryos were collected at three minute intervals over the three cell cycles leading up to the MBT (nuclear cycles 11, 12, and 13). Embryos were subjected to ATAC-seq library preparation following established protocols. Thirteen total timepoints were collected. At least three biological replicates were collected per timepoint. Samples were subjected to paired end sequencing on an Illumina HiSeq 2500. Wild type (diploid) embryos were compared with haploid (sesame) embryos to determine whether changes in chromatin accessibility are governed by measurement of the nucleo-cytoplasmic ratio, a well known biological timer that controls the onset of the MBT. Results: Chromatin accessibility changes dynamically during the period leading up to the MBT. Initially, genomic enhancer elements are accessible, but during NC12 and NC13, large scale chromatin remodeling results in a gain of accessibility for promoter elements and insulators. A substantial fraction of the dynamic chromatin accessibility is temporally regulated by the mechanism that measures the embryonic nuclear-cytoplasmic ratio, as determined by comparison between haploid and diploid embryos. A substantial fraction of open chromatin regions remain 'accessible' during mitotic metaphase.
