DNA-replication checkpoint control at the Drosophila midblastula transition
TLDR
This article showed that mutations in the grapes (grp) checkpoint 1 kinase homologue in Drosophila block the morphological and biochemical changes that accompany the midblastula transition, leading to a continuation of the maternal cell-cycle programme, and disrupt DNA-replication checkpoint control of cell cycle progression.Abstract:
Embryogenesis is typically initiated by a series of rapid mitotic divisions that are under maternal genetic control. The switch to zygotic control of embryogenesis at the midblastula transition is accompanied by significant increases in cell-cycle length and gene transcription, and changes in embryo morphology. Here we show that mutations in the grapes (grp) checkpoint 1 kinase homologue in Drosophila block the morphological and biochemical changes that accompany the midblastula transition, lead to a continuation of the maternal cell-cycle programme, and disrupt DNA-replication checkpoint control of cell-cycle progression. The timing of the midblastula transition is controlled by the ratio of nuclei to cytoplasm (the nucleocytoplasmic ratio), suggesting that this developmental transition is triggered by titration of a maternal factor by the increasing mass of nuclear material that accumulates during the rapid embryonic mitoses. Our observations support a model for cell-cycle control at the midblastula transition in which titration of a maternal component of the DNA-replication machinery slows DNA synthesis and induces a checkpoint-dependent delay in cell-cycle progression. This delay may allow both completion of S phase and transcription of genes that initiate the switch to zygotic control of embryogenesis.read more
Citations
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Rif1 prolongs the embryonic S phase at the Drosophila mid-blastula transition.
TL;DR: This work found that Cdk1 activity inhibited the chromatin association of Rap1 interacting factor 1 (Rif1), a candidate repressor of replication, and shows that Rif1 and S phase kinases compose a replication timer controlling first the developmental onset of late replication and then the precise schedule of replication within S phase.
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The Endo-siRNA Pathway Is Essential for Robust Development of the Drosophila Embryo
TL;DR: It is shown that the genes DICER-2 and ARGONAUTE2, which code for integral protein components of the endo-siRNA pathway, are essential for robust development and temperature compensation in the Drosophila embryo when exposed to temperature perturbations, and it is hypothesized that the enda-siRNAs may regulate the degradation of maternal cell cycle regulators.
Journal ArticleDOI
Developmentally Regulated Elimination of Damaged Nuclei Involves a Chk2-Dependent Mechanism of mRNA Nuclear Retention
Carole Iampietro,Julie Bergalet,Xiaofeng Wang,Neal A.L. Cody,Ashley Chin,Fabio Alexis Lefebvre,Mélanie Douziech,Henry M. Krause,Eric Lécuyer,Eric Lécuyer +9 more
TL;DR: It is shown that nuclear retention involves a Chk2-dependent mechanism of mRNA nuclear retention that is induced by DNA damage and prevents the translation of specific zygotic mRNAs encoding key mitotic, cytoskeletal, and nuclear proteins required to maintain nuclear viability.
Journal ArticleDOI
Dominant‐negative mutants reveal a role for the Cdk7 kinase at the mid‐blastula transition in Drosophila embryos
TL;DR: It is suggested that a distinct pool of CAK activity that is unaffected by expression of the cdk7DN mutants is present in these embryos, which implicate Cdk7 in the control of transcriptional machinery in vivo.
Journal ArticleDOI
Histone concentration regulates the cell cycle and transcription in early development
TL;DR: Overexpression or knockdown of histones results in delayed or advanced cell cycle slowing and transcriptional activation at the mid-blastula transition, respectively, with differentially expressed genes associated with specific chromatin features.
References
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A non-radioactive in situ hybridization method for the localization of specific RNAs in Drosophila embryos reveals translational control of the segmentation gene hunchback.
Diethard Tautz,Christine Pfeifle +1 more
TL;DR: A non-radioactive in situ hybridization technique for the localization of RNA in whole mount Drosophila embryos and revealed translational control of the maternally derived hb mRNA, which was difficult to detect by conventional techniques.
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TL;DR: The Xenopus embryo undergoes 12 rapid synchronous cleavages followed by a period of slower asynchronous divisions more typical of somatic cells, termed the midblastula transition (MBT), which shows that at the MBT the blastomeres become motile and transcriptionally active for the first time.
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V.E. Foe,B.M. Alberts +1 more
TL;DR: Using differential interference contrast optics, combined with cinematography, the morphological changes that the living, syncytial embryo undergoes from stage 10 through 14 of Drosophila embryogenesis, that is just prior to and during formation of the cellular blastoderm are studied.