Project description:It has long been appreciated that striped pair-rule transcription factor expression is necessary for convergent extension in the early Drosophila embryo, although the mechanisms that link these transcriptional regulators to planar polarity in this tissue have long been elusive. The goal of this study was to determine the transcriptional tragets of the pair-rule transcription factors Eve and Runt in Drosophila blastoderm embryos. We compared the transcriptional profiles of late blastoderm embryos injected with either water or dsRNAs against both eve and runt to identify differentially expressed genes that may directly contribute to the establishment of planar polarity during Drosophila convergent extension. Comparing the mRNA profiles from late blastoderm Drosophila embryos injected with either water (Water) or eve+runt dsRNAs (Eve), in triplicate, using Illumina HiSeq.
Project description:It has long been appreciated that striped pair-rule transcription factor expression is necessary for convergent extension in the early Drosophila embryo, although the mechanisms that link these transcriptional regulators to planar polarity in this tissue have long been elusive. The goal of this study was to determine the transcriptional tragets of the pair-rule transcription factors Eve and Runt in Drosophila blastoderm embryos. We compared the transcriptional profiles of late blastoderm embryos injected with either water or dsRNAs against both eve and runt to identify differentially expressed genes that may directly contribute to the establishment of planar polarity during Drosophila convergent extension.
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:Pioneer factors such as Zelda (Zld) help initiate zygotic transcription in Drosophila early embryos, but whether other factors support this dynamic process is unclear. Odd-paired (Opa), a zinc-finger transcription factor expressed at cellularization, controls the transition of genes from pair-rule to segmental patterns along the anterior-posterior axis. Finding that Opa also regulates expression through enhancer sog_Distal along the dorso-ventral axis, we hypothesized Opa’s role is more general. Chromatin-immunoprecipitation (ChIP-seq) confirmed its in vivo binding to sog_Distal but also identified widespread binding throughout the genome, comparable to Zld. Furthermore, chromatin assays (ATAC-seq) demonstrate that Opa, like Zld, influences chromatin accessibility genome-wide at cellularization, suggesting both are pioneer factors with common as well as distinct targets. Lastly, embryos lacking opa exhibit widespread, late patterning defects spanning both axes. Collectively, these data suggest Opa is a general timing factor and likely late-acting pioneer factor that drives a secondary wave of zygotic gene expression contributor: Theodora Koromila (ATAC-seq-RNA-seq) contributor: Fan Gao (Bioinformatic analysis) contributor: Angelike Stathopoulos (PI) contributor: Peng He (Bioinformatic analysis)
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:Pioneer factors such as Zelda initiate zygotic transcription within Drosophila early embryos, but whether other factors also support this dynamic patterning process is unclear. Odd-paired (Opa) is a zinc-finger transcription factor expressed during cellularization, shown to act as timing factor to control pair-rule to segmental patterning transition along the anterior-posterior (AP) axis. We found Opa regulates expression through an enhancer active along the dorso-ventral axis (sog_Distal), specifically, to support its late embryonic expression. Opa chromatin immunoprecipitation identified occupancy at this enhancer sequence as well widespread binding throughout the genome, comparable to Zelda. Furthermore, chromatin assays (ATAC-seq) demonstrate that Opa, like Zelda, influences accessibility and has both common as well as distinct target sequences. opa mutants also exhibit DV and AP patterning changes suggesting Opa acts broadly. This study suggests Opa is a late-acting, pioneer factor whose action follows Zelda to herald in a second wave of zygotic gene expression. NIH Grants R35GM118146 and R03HD097535 to A.S.
Project description:The orphan nuclear receptor Ftz-F1 is expressed in all somatic nuclei in Drosophila embryos but mutations result in a pair-rule phenotype. Previously characterized Ftz-F1 target genes were co-regulated by Ftz, which is expressed in stripes, consistent with the pair-rule phenotype observed for ftz-f1 and ftz mutants. However, attempts to identify new target genes on the basis of Ftz-F1 and Ftz binding sites alone has met with only limited success. To discern the rules for Ftz-F1 target site selection in vivo and to identify additional target genes, a microarray analysis was performed comparing wildtype and ftz-f1 mutant embryos.
Project description:Purpose: Combination of systemic RNAi with RNAseq to identify target genes of important pathways in early development Drosophila early patterning occurs in the syncytial blastoderm where transcription factors diffuse between cells. However, in typical insect embryos, patterning occurs in a cellularized environment where signaling pathways are likely to play a more fundamental role. We use the short germ beetle Tribolium castaneum to investigate two putative Wnt and Hh signaling centers located in the anlagen of head and growth zone. These structures are known to develop in a different way in short germ insects. We find that Hh acts upstream of Wnt in the head, which is different from the Drosophila situation. In the growth zone Wnt signaling acts upstream. For the first time outside Drosophila, we comprehensively determine the Wnt and Hh target gene sets and distinguish the anterior from the posterior gene sets by genetically depleting head or growth zone. Surprisingly, there are significantly more targets in the growth zone than in the head for both pathways and we find that their growth zone gene sets are essentially non-overlapping. Furthermore, several pair rule genes, Tc-caudal, Tc-twist and hindgut patterning genes are regulated by Wnt signaling. In addition, Wnt controls growth zone metabolism and cell division. Posterior Hh signaling activates several genes potentially involved in a proteinase cascade of unknown function. Unexpectedly, we find the Wnt target Tc-senseless to be required for hindgut development. 10-11 h old whole embyro mRNA profiles of the following treatments: reference: wild type 100bp single read triplicates reference: wild type 50bp single read triplicates treatment: Tc-arrow RNAi knockdown 50 bp single read triplicates treatment: Tc-frizzled1/2 RNAi double knockdown 50 bp single read triplicates treatment: Tc-hedgehog RNAi knockdown 100bp single reads quadruplicates treatment: Tc-orthodenticle RNAi knockdown 100bp single reads triplicates treatment: Tc-torso RNAi knockdown 100bp single reads triplicates treatment: Tc-wntless RNAi knockdown 50bp single reads triplicates Total: 2 references, 6 treatments, 25 sequencing runs