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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DNA defects target the centrosome.
Smruti J. Vidwans,Tin Tin Su +1 more
TL;DR: When cells enter mitosis with DNA that is unfit to be segregated, the consequences appear to be loss of centrosome function, abnormal spindles and a failure to segregate chromosomes.
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Emerging mechanisms regulating mitotic synchrony during animal embryogenesis
Yosuke Ogura,Yasunori Sasakura +1 more
TL;DR: This review is an attempt to understand the temporal patterns of cleavages in animal embryos created by the combinations of these three mechanisms: biochemical switches that achieve the synchrony of mitosis, the nucleo‐cytoplasmic ratio that provokes the asynchrony ofMitosis, and the transcriptional mechanisms coupled with cell fate control that reestablish the synchronies in each fate‐restricted compartment.
Journal ArticleDOI
Cell cycle defects in polyhomeotic mutants are caused by abrogation of the DNA damage checkpoint
TL;DR: The data show that the mitotic defects of ph(p) are caused by defects in the DNA damage response that occurs after DNA replication in S phase, and it is proposed that PhP has a direct role in DNA damage repair.
Journal ArticleDOI
Cullin-5 mutants reveal collective sensing of the nucleocytoplasmic ratio in Drosophila embryogenesis
L.D. Hayden,Anna T. Chao,Victoria E. Deneke,Massimo Vergassola,Alberto Puliafito,Stefano Di Talia +5 more
TL;DR: In this paper , a new pathway controlling nuclear positioning and dissection of how nuclear cycles respond to the N/C ratio is provided. But the pathway is not fully elucidated.
Journal ArticleDOI
The Nuclear-to-Cytoplasmic Ratio: Coupling DNA Content to Cell Size, Cell Cycle, and Biosynthetic Capacity.
TL;DR: This work explores how cells couple cell division and growth to DNA content and suggests a causative, not simply correlative, role for the N/C ratio in regulating cell growth and cell cycle progression.
References
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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.