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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Spindle assembly checkpoint acquisition at the mid-blastula transition.
TL;DR: Using zebrafish embryos, it is shown that SAC acquisition at the MBT is independent of zygotic transcription, indicating that the checkpoint program is maternally supplied and that Sac acquisition can be uncoupled from the N:C ratio.
Journal ArticleDOI
Chk1 Inhibition of the Replication Factor Drf1 Guarantees Cell-Cycle Elongation at the Xenopus laevis Mid-blastula Transition
TL;DR: It is shown that developmental activation of the checkpoint kinase Chk1 at the MBT results in the SCFβ-TRCP-dependent degradation of a limiting replication initiation factor Drf1.
Journal ArticleDOI
Onset of the DNA replication checkpoint in the early Drosophila embryo.
TL;DR: It is proposed that lowered dRPA2 levels activate Grp/Chk1 to counteract excess Cdk1–CycB activity and restore interphase duration and the ability to block mitosis in response to aphidicolin.
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Argonaute-1 functions as a mitotic regulator by controlling Cyclin B during Drosophila early embryogenesis
S.N.C.V.L. Pushpavalli,Arpita Sarkar,Indira Bag,Clayton R. Hunt,M. Janaki Ramaiah,Tej K. Pandita,Utpal Bhadra,Manika Pal-Bhadra +7 more
TL;DR: It is demonstrated that the haploinsufficiency of maternal Ago‐1 disrupts mitotic chromosome segregation and spindle fiber assembly via miRNA‐guided control during early embryogenesis in Drosophila through involvement of 2 novel embryonic miRNAs—miR‐981 and miR‐317—for spatiotemporal regulation of cyclin B.
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Tumor suppressor Lzap regulates cell cycle progression, doming, and zebrafish epiboly
Dan Liu,Wen-Der Wang,David B. Melville,Yong I. Cha,Zhirong Yin,Natalia Issaeva,Ela W. Knapik,Wendell G. Yarbrough +7 more
TL;DR: The results strongly implicate Lzap in regulation of cell cycle progression, adhesion and migratory activity of epithelial cell sheets during early development, and provide further insight into LZap activity that may contribute not only to development, but also to tumor formation.
References
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