Concentration dependent binding states of the Bicoid Homeodomain Protein
Ontology highlight
ABSTRACT:
ORGANISM(S): Drosophila melanogaster
PROVIDER: GSE86966 | GEO | 2017/09/11
SECONDARY ACCESSION(S): PRJNA343106
REPOSITORIES: GEO
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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.
2015-07-22 | GSE71137 | GEO
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.
2015-07-22 | E-GEOD-71137 | biostudies-arrayexpress
Project description:These experiments measure genome-wide RNA Pol II binding in precisely staged wild-type embryos at five time points spanning the maternal to zygotic transition (nuclear cycles 12 through 14) of Drosophila melanogaster. In addition, RNA Pol II binding at nuclear cycle 13 is measured in embryos mutant for either mei-41/ATR or zelda. To correlate RNA Pol II binding with replication stress, genome-wide profiles of Replication protein A (70kDa subunit, RpA-70 EGFP) were generated in parallel with RNA Pol II for both wild-type and zelda at nuclear cycle 13.
2015-03-05 | GSE62925 | GEO
Project description:These experiments measure genome-wide RNA Pol II binding in precisely staged wild-type embryos at five time points spanning the maternal to zygotic transition (nuclear cycles 12 through 14) of Drosophila melanogaster. In addition, RNA Pol II binding at nuclear cycle 13 is measured in embryos mutant for either mei-41/ATR or zelda. To correlate RNA Pol II binding with replication stress, genome-wide profiles of Replication protein A (70kDa subunit, RpA-70 EGFP) were generated in parallel with RNA Pol II for both wild-type and zelda at nuclear cycle 13. Two replicates each for 5 time points for wild type RNA Pol II. Two replicates for mei-41 RNA Pol II, nuclear cycle 13. Two replicates for zelda RNA Pol II, nuclear cycle 13. Two replicates each for Rpa70-EGFP in wild-type or zelda, nuclear cycle 13, matched to the corresponding RNA Pol II sample.
2015-03-05 | E-GEOD-62925 | biostudies-arrayexpress
Project description:In vivo crosslinking studies suggest that the Drosophila transcription factor Bicoid (Bcd) binds to several thousand sites during early embryogenesis, but it is not clear how many of these binding events are functionally important. In contrast, reporter gene studies have identified more than 60 Bcd-dependent enhancers, all of which contain clusters of the consensus binding sequence TAATCC. These studies also identified clusters of TAATCC motifs (inactive fragments) that failed to drive Bcd-dependent activation. In general, active fragments showed higher levels of Bcd-binding in vivo, and were enriched in predicted binding sites for the ubiquitous maternal protein Zelda (Zld). Here we test the role of Zld in Bcd-mediated binding and transcription. Removal of Zld function and mutations in Zld sites caused significant reductions in Bcd-binding to known enhancers, and variable effects on the activation and spatial positioning of Bcd-dependent expression patterns. Genome-wide binding experiments in Zld mutants showed variable effects on Bcd-binding peaks, ranging from strong reductions to significantly enhanced levels of binding. Increases in Bcd binding caused the precocious Bcd-dependent activation of genes that are normally not expressed in early embryos, suggesting that Zld controls the genome-wide binding profile of Bcd at the qualitative level, and is critical for selecting target genes for activation in the early embryo. These results underscore the importance of combinatorial binding in enhancer function, and provide data that will help predict regulatory activities based on DNA sequence. 1-3 hour wild type and zelda mutant embryos were examined for Bicoid binding using Illumina HiSeq 2000. The Bcd antibody is a rabbit polyclonal antiserum raised against full length Drosophila Bcd protein (Ochoa-Espinosa et al. 2009 PNAS). The antiserum was further purified using the Protein A Antibody Purification Kit (Sigma) for ChIP-seq.
2014-05-02 | E-GEOD-55256 | biostudies-arrayexpress
Project description:A conspicuous feature of early animal development is the lack of transcription from the embryonic genome, and it typically takes several hours to several days (depending on the species) until widespread transcription of the embryonic genome begins. Although this transition is ubiquitous, relatively little is known about how the shift from a transcriptionally quiescent to transcriptionally active genome is controlled. We describe here the genome-wide distributions and temporal dynamics of nucleosomes and post-translational histone modifications through the maternal-to-zygotic transition in embryos of the pomace fly Drosophila melanogaster. At mitotic cycle 8, when few zygotic genes are being transcribed, embryonic chromatin is in a relatively simple state: there are few nucleosome-free regions, undetectable levels of the histone methylation marks characteristic of mature chromatin, and low levels of histone acetylation at a relatively small number of loci. Histone acetylation increases by cycle 12, but it is not until cycle 14 that nucleosome-free regions and domains of histone methylation become widespread. Early histone acetylation is strongly associated with regions that we have previously shown are bound in early embryos by the maternally deposited transcription factor Zelda. Most of these Zelda-bound regions are destined to be enhancers or promoters active during mitotic cycle 14, and our data demonstrate that they are biochemically distinct long before they become active, raising the possibility that Zelda triggers a cascade of events, including the accumulation of specific histone modifications, that plays a role in the subsequent activation of these sequences. Many of these Zelda-associated active regions occur in larger domains that we find strongly enriched for histone marks characteristic of Polycomb-mediated repression, suggesting a dynamic balance between Zelda activation and Polycomb repression. Collectively, these data paint a complex picture of a genome in transition from a quiescent to an active state, and highlight the role of Zelda in mediating this transition. We performed genome-wide mapping of histone H3 and 9 types of histone modifications, including H4K5ac, H4K8ac, H3K4me1, H3K4me3, H3K27me3, H3K36me3, H3K9ac, H3K18ac, and H3K27ac by ChIP-seq, in hand-sorted wild-type Drosophila melanogaster embryos at 4 different development time points corresponding to mitotic cycle 7-9, 11-13, 14a-b, and 14c-d, respectively. We also carried out ChIP-seq experiments in zelda mutant embryos after showing that the deposition of histone marks in early embryos strongly correlated with the binding of Zelda in wild-type embryos.
2014-10-16 | E-GEOD-58935 | biostudies-arrayexpress
Project description:During the first stages of development, the fertilized germ cells rapidly transition to totipotency. Maternally deposited mRNAs encode the proteins necessary for reprogramming the transcriptionally quiescent zygotic genome during this maternal-to-zygotic transition (MZT). The transcription factor Zelda is essential for this reprogramming in the Drosophila embryo. Zelda is necessary for transcriptional activation of the zygotic genome, and the absence of Zelda leads to embryonic lethality during the MZT. Excess Zelda activity is also lethal to the embryo, demonstrating that Zelda levels must be precisely controlled during early development. Because Zelda is encoded by a maternally deposited mRNA, Zelda levels in the embryo are controlled at the level of translation. To understand how levels of this essential reprogramming factor were regulated to allow for embryonic development and zygotic genome activation, we investigated the factors that regulated translation of zelda. Brain Tumor (BRAT) is a translational regulator that was previously shown to bind to zelda mRNA in the embryo. We showed that BRAT functions to repress zelda translation, as embryos deficient for maternal BRAT activity prematurely express Zelda. We further showed that in the larval brain, BRAT similarly regulates Zelda levels and identified specific BRAT-binding sites that mediate these effects. Thus, BRAT regulates Zelda in multiple tissues. Because both too little and too much Zelda are lethal to the embryo, we hypothesized that precocious expression of this transcriptional activator might be capable of driving precocious activation of the zygotic genome, leading to embryonic lethality. To test this hypothesis, we performed single embryo RNA-seq at distinct nuclear cycles throughout zygotic genome activation (NC10, NC12, NC13, and NC14) in control and brat-mutant embryos. Our results conclusively demonstrated that in embryos lacking functional BRAT, Zelda target genes were not prematurely activated. Rather, these genes were expressed normally, but become significantly upregulated at nuclear cycle 14, when the division cycle slows. Our data support a model in which zygotic genome activation requires precise coordination between expression of reprogramming factors, such as Zelda, and the slowing of the cell cycle.
2022-06-17 | GSE197582 | GEO
Project description:ChIP-Seq against Bicoid on manually dissected posterior thirds of Drosophila Melanogaster early stage 5 embryos.
2017-10-04 | GSE103695 | GEO
Project description:Morphogen gradients expose cells to different signal concentrations and induce target genes with different ranges of expression. To determine how the Nodal morphogen gradient induces distinct gene expression patterns during zebrafish embryogenesis we characterized the binding sites of the Nodal-specific transcription co-activators Smad2 and FoxH1 in wild-type, Nodal-overexpressing or Nodal signaling inhibited embryos. We found that FoxH1 binds to Nodal targets loci even in the absence of the signal, while Smad2 only binds and colocalizes to FoxH1 upon induction of the Nodal pathway.
2015-04-08 | GSE67648 | GEO
Project description:A long-standing question in the field of embryogenesis is how the zygotic genome is precisely activated by maternal factors, allowing normal early embryonic development. We have previously shown that N6-methyladenine (6mA) DNA modification is highly dynamic in early Drosophila embryos and forms an epigenetic mark. However, little is known about how 6mA-formed epigenetic information is decoded. Here we report that the Fox-family protein Jumu binds 6mA-marked DNA and acts as a maternal factor to regulate the maternal-to-zygotic transition. We find that zelda encoding the pioneer factor Zelda is marked by 6mA. Our genetic assays suggest that Jumu controls the proper zygotic genome activation (ZGA) in early embryos, at least in part, by regulating zelda expression. Thus, our findings not only support that the 6mA-formed epigenetic can be read by specific transcription factors, but also uncover a mechanism by which the Jumu regulates ZGA partially through Zelda in early embryos.
2019-04-18 | GSE86795 | GEO