Interphase-arrested Drosophila embryos activate zygotic gene expression and initiate Mid-Blastula Transition events at a low nuclear-cytoplasmic ratio
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ABSTRACT:
PROVIDER: PRJNA646497 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR12230016_1.fastq.gz | Fastqsanger.gz | |||
| SRR12230016_2.fastq.gz | Fastqsanger.gz | |||
| SRR12230017_1.fastq.gz | Fastqsanger.gz | |||
| SRR12230017_2.fastq.gz | Fastqsanger.gz | |||
| SRR12230018_1.fastq.gz | Fastqsanger.gz |
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Project description:Externally deposited eggs begin development with an immense cytoplasm and a single overwhelmed nucleus. Rapid mitotic cycles restore normality as the ratio of nuclei to cytoplasm (N/C) increases. A threshold N/C has been widely proposed to activate zygotic genome transcription and onset of morphogenesis at the mid-blastula transition (MBT). To test whether a threshold N/C is required for these events, we blocked N/C-increase by downregulating cyclin/Cdk1 to arrest early cell cycles in Drosophila. Embryos that were arrested two cell cycles prior to the normal MBT activated widespread transcription of the zygotic genome including genes previously described as N/C-dependent. Zygotic transcription of these genes largely retained features of their regulation in space and time. Furthermore, zygotically regulated post-MBT events such as cellularization and gastrulation movements occurred in these cell-cycle-arrested embryos. These results are not compatible with models suggesting that these MBT events are directly coupled to N/C. Cyclin/Cdk1 activity normally declines in tight association with increasing N/C and is regulated by N/C. By experimentally promoting the decrease in cyclin/Cdk1, we uncoupled MBT from N/C increase, arguing that N/C guided down-regulation of cyclin/Cdk1 is sufficient for genome activation and MBT.
2020-08-15 | GSE154502 | GEO
Project description:Externally deposited eggs begin development with an immense cytoplasm and a single overwhelmed nucleus. Rapid mitotic cycles restore normality as the ratio of nuclei to cytoplasm (N/C) increases. A threshold N/C has been widely proposed to activate zygotic genome transcription and onset of morphogenesis at the mid-blastula transition (MBT). To test whether a threshold N/C is required for these events, we blocked N/C increase by down-regulating cyclin/Cdk1 to arrest early cell cycles in Drosophila. Embryos that were arrested two cell cycles prior to the normal MBT activated widespread transcription of the zygotic genome including genes previously described as N/C dependent. Zygotic transcription of these genes largely retained features of their regulation in space and time. Furthermore, zygotically regulated post-MBT events such as cellularization and gastrulation movements occurred in these cell cycle-arrested embryos. These results are not compatible with models suggesting that these MBT events are directly coupled to N/C. Cyclin/Cdk1 activity normally declines in tight association with increasing N/C and is regulated by N/C. By experimentally promoting the decrease in cyclin/Cdk1, we uncoupled MBT from N/C increase, arguing that N/C-guided down-regulation of cyclin/Cdk1 is sufficient for genome activation and MBT.
| S-EPMC7608951 | biostudies-literature
Project description:Sox31 is a member of the zebrafish SoxB1 subfamily, and its expression can be detected both pre- and post-MBT. To distinguish the function of its maternal and zygotic transcripts, a splice blocking morpholino (Sb MO) was designed to interfere with the processing of new, zygotically synthesised mRNAs without interfering with mRNAs of maternal origin. Developmental arrest was observed in Sb MO which could not bypass MBT. Mid-Blastula Transition (MBT) functions as a time window for zygotic genome activation and maternal mRNA degradation. To uncover whether the “zygotic up” and “maternal down” event during MBT is retarded in Sb morphants, we performed microarray experiment at the end of MBT (about 4.3 hours post fertilication/4.3 hpf) to compare mRNAs from Sb morphants and control embryos.
2011-10-13 | GSE32914 | GEO
Project description:Mixed Lineage Leukemia (MLL) and its metazoan Trithorax orthologs have been linked with the epigenetic maintenance of transcriptional activity. To identify mechanisms by which MLL perpetuates active transcription in dividing cells, we investigated its role during M-phase of the cell cycle. Unlike other chromatin modifying enzymes examined, we found that MLL associates with gene promoters packaged within condensed mitotic chromosomes. Genome-wide location analysis identified a globally rearranged pattern of MLL occupancy during mitosis in a manner favoring genes that were highly transcribed during interphase. Knockdown experiments revealed that MLL retention at gene promoters during mitosis accelerates transcription reactivation following mitotic exit. MLL tethers Menin, RbBP5, and ASH2L to its occupied sites during mitosis, but is dispensable for preserving histone H3K4 methylation. These findings implicate mitotic bookmarking as a component of Trithorax-based gene regulation which may facilitate inheritance of active gene expression states during cell division. anti-MLL ChIP (antibody 456) and anti-pol2 chip (sc-899) in chromatin prepared from interphase and mitotic HeLa cells
2010-05-19 | E-GEOD-19155 | biostudies-arrayexpress
Project description:Sox31 is a member of the zebrafish SoxB1 subfamily, and its expression can be detected both pre- and post-MBT. To distinguish the function of its maternal and zygotic transcripts, a splice blocking morpholino (Sb MO) was designed to interfere with the processing of new, zygotically synthesised mRNAs without interfering with mRNAs of maternal origin. Developmental arrest was observed in Sb MO which could not bypass MBT. Mid-Blastula Transition (MBT) functions as a time window for zygotic genome activation and maternal mRNA degradation. To uncover whether the “zygotic up” and “maternal down” event during MBT is retarded in Sb morphants, we performed microarray experiment at the end of MBT (about 4.3 hours post fertilication/4.3 hpf) to compare mRNAs from Sb morphants and control embryos. In one experiment, three flocks of zebrafish eggs were injected with the Sox19b morpholino immediately after fertilization, while another three control populations were injected with placebo. At 4.3 hpf, these six flocks of embryos were sent for gene expression profiling with six Affymetrix Zebrafish Genome Arrays. In another experiment, we compared two wildtype embryo samples at 4h (post-MBT) against two wildtype samples at 2.5 h (pre-MBT).
2011-10-12 | E-GEOD-32914 | biostudies-arrayexpress
Project description:In most embryos, the mid-blastula transition is a complex process featuring maternal RNA degradation, cell cycle pause, zygotic transcriptional activation and morphological changes. The nucleocytoplasmic (N/C) ratio has been proposed to control the multiple events at MBT. To understand the global transcriptional response to the changes of the N/C ratio, we profiled wild type and haploid embryos using cDNA microarrays at three developmental stages. Experiment Overall Design: For the diploid transcriptional profile, we prepared cDNA from hand selected wild-type embryos at cycle 13 interphase (15min after the nuclear division of cycle 12) and at early and late cycle 14 interphase (15min and 40 min after the nuclear division of cycle 13), respectively. For the haploid, cDNA was prepared from cycle 14 embryos (15min after the nuclear division of cycle 13) and early and late cycle 15 embryos (15min and 40 minutes after the nuclear division of cycle 14). The collection was designed in this way so that each cell cycle stage of the diploid has a counterpart stage with matched N/C ratio in the haploid (e.g. cycle 13 in the diploid has the same N/C ratio as cycle 14 in the haploid). In all experiments, the cell cycle progression was monitored by the Histone-GFP pattern. Triplicates of about 50 embryos each with right age were collected for each time point.
2009-06-24 | E-GEOD-14287 | biostudies-arrayexpress
Project description:RNA-DNA duplexes have been extensively catalogued in interphase cells, but relatively little is known about the genomic loci of these duplexes in mitotic cells. We compared RNA-DNA duplexes in DLD1 cells arrested in mitosis to libraries previously published in asynchronous HEK293T cells prepared with the same protocols, and processed with the same bioinformatic pipeline. We also observed that Aurora B inhibitors increased the immunofluorescence signal for RNA-DNA duplexes in mitotic cells, so we tested the effect of Aurora B inhibition on genomic enrichment of RNA-DNA duplexes.
2021-02-28 | GSE163197 | GEO
Project description:Mixed Lineage Leukemia (MLL) and its metazoan Trithorax orthologs have been linked with the epigenetic maintenance of transcriptional activity. To identify mechanisms by which MLL perpetuates active transcription in dividing cells, we investigated its role during M-phase of the cell cycle. Unlike other chromatin modifying enzymes examined, we found that MLL associates with gene promoters packaged within condensed mitotic chromosomes. Genome-wide location analysis identified a globally rearranged pattern of MLL occupancy during mitosis in a manner favoring genes that were highly transcribed during interphase. Knockdown experiments revealed that MLL retention at gene promoters during mitosis accelerates transcription reactivation following mitotic exit. MLL tethers Menin, RbBP5, and ASH2L to its occupied sites during mitosis, but is dispensable for preserving histone H3K4 methylation. These findings implicate mitotic bookmarking as a component of Trithorax-based gene regulation which may facilitate inheritance of active gene expression states during cell division.
2009-11-25 | GSE19155 | GEO
Project description:Background: Structural maintenance of chromosomes (SMC) complexes are central organizers of chromatin architecture throughout the cell cycle. The SMC family member condensin is best known for establishing long-range chromatin interactions in mitosis. These compact chromatin and create mechanically stable chromosomes. How condensin contributes to chromatin organization in interphase is less well understood. Results: Here, we use efficient conditional depletion of fission yeast condensin to determine its contribution to interphase chromatin organization. We deplete condensin in G2 arrested cells to preempt confounding effects from cell cycle progression without condensin. Genome-wide chromatin interaction mapping, using Hi-C, reveals condensin-mediated chromatin interactions in interphase that are qualitatively similar to those observed in mitosis, but quantitatively far less prevalent. Despite its low abundance, chromatin mobility tracking shows that condensin markedly confines interphase chromatin movements. Without condensin, chromatin behaves as an unconstrained Rouse polymer with excluded volume, while condensin constrains its mobility. Unexpectedly, we find that condensin is required during interphase to prevent ongoing transcription from eliciting a DNA damage response. Conclusions: In addition to establishing mitotic chromosome architecture, condensin-mediated long-range chromatin interactions contribute to shaping chromatin organization in interphase. The resulting structure confines chromatin mobility and protects the genome from transcription-induced DNA damage. This adds to the important roles of condensin in maintaining chromosome stability.
2020-09-14 | GSE143338 | GEO
Project description:We report the genomic localization of cohesin oligomers in nocodazole arrested yeast cells. Two alleles of SMC3 were expressed in yeast cells, one fused to BirA enzyme and the other tagged with AviTag. Cohesin oligomers were biotinylated and ChIP with streptavidin beads. As control experiments, cohesin localization on chromosome was determined in strains expresses freely diffusable BirA enzyme, where all Smc3 proteins were biotinylated; non-specific ChIP were determined in strains with no BirA.
2020-08-31 | GSE157155 | GEO