scholarly journals Both Cyclin B levels and DNA-replication checkpoint control the early embryonic mitoses in Drosophila

Development ◽  
2003 ◽  
Vol 131 (2) ◽  
pp. 401-411 ◽  
Author(s):  
J.-Y. Ji
BioEssays ◽  
2007 ◽  
Vol 29 (10) ◽  
pp. 949-952
Author(s):  
Dhananjay Yellajoshyula ◽  
Ethan S. Patterson ◽  
Kristen L. Kroll

2004 ◽  
Vol 279 (45) ◽  
pp. 47372-47378 ◽  
Author(s):  
Izumi Sugimoto ◽  
Hiroshi Murakami ◽  
Yuko Tonami ◽  
Akihiko Moriyama ◽  
Makoto Nakanishi

1998 ◽  
Vol 111 (20) ◽  
pp. 3101-3108 ◽  
Author(s):  
E. Greenwood ◽  
H. Nishitani ◽  
P. Nurse

The DNA replication checkpoint is required to maintain the integrity of the genome, inhibiting mitosis until S phase has been successfully completed. The checkpoint preventing premature mitosis in Schizosaccharomyces pombe relies on phosphorylation of the tyrosine-15 residue on cdc2p to prevent its activation and hence mitosis. The cdc18 gene is essential for both generating the DNA replication checkpoint and the initiation of S phase, thus providing a key role for the overall control and coordination of the cell cycle. We show that the C terminus of the protein is capable of both initiating DNA replication and the checkpoint function of cdc18p. The C terminus of cdc18p acts upstream of the DNA replication checkpoint genes rad1, rad3, rad9, rad17, hus1 and cut5 and requires the wee1p/mik1p tyrosine kinases to block mitosis. The N terminus of cdc18p can also block mitosis but does so in the absence of the DNA replication checkpoint genes and the wee1p/mik1p kinases therefore acting downstream of these genes. Because the N terminus of cdc18p associates with cdc2p in vivo, we suggest that by binding the cdc2p/cdc13p mitotic kinase directly, it exerts an effect independently of the normal checkpoint control, probably in an unphysiological manner.


2004 ◽  
Vol 167 (5) ◽  
pp. 841-849 ◽  
Author(s):  
Ayumi Yamada ◽  
Brad Duffy ◽  
Jennifer A. Perry ◽  
Sally Kornbluth

G2/M checkpoints prevent mitotic entry upon DNA damage or replication inhibition by targeting the Cdc2 regulators Cdc25 and Wee1. Although Wee1 protein stability is regulated by DNA-responsive checkpoints, the vertebrate pathways controlling Wee1 degradation have not been elucidated. In budding yeast, stability of the Wee1 homologue, Swe1, is controlled by a regulatory module consisting of the proteins Hsl1 and Hsl7 (histone synthetic lethal 1 and 7), which are targeted by the morphogenesis checkpoint to prevent Swe1 degradation when budding is inhibited. We report here the identification of Xenopus Hsl7 as a positive regulator of mitosis that is controlled, instead, by an entirely distinct checkpoint, the DNA replication checkpoint. Although inhibiting Hsl7 delayed mitosis, Hsl7 overexpression overrode the replication checkpoint, accelerating Wee1 destruction. Replication checkpoint activation disrupted Hsl7–Wee1 interactions, but binding was restored by active polo-like kinase. These data establish Hsl7 as a component of the replication checkpoint and reveal that similar cell cycle control modules can be co-opted for use by distinct checkpoints in different organsims.


2011 ◽  
Vol 193 (2) ◽  
pp. 267-273 ◽  
Author(s):  
Jiadong Wang ◽  
Zihua Gong ◽  
Junjie Chen

Human TopBP1 is a major player in the control of the DNA replication checkpoint. In this study, we identified MDC1, a key checkpoint protein involved in the cellular response to DNA double-strand breaks, as a TopBP1-associated protein. The specific TopBP1–MDC1 interaction is mediated by the fifth BRCT domain of TopBP1 and the Ser-Asp-Thr (SDT) repeats of MDC1. In addition, we demonstrated that TopBP1 accumulation at stalled replication forks is promoted by the H2AX/MDC1 signaling cascade. Moreover, MDC1 is important for ATR-dependent Chk1 activation in response to replication stress. Collectively, our data suggest that MDC1 facilitates several important steps in both cellular DNA damage response and the DNA replication checkpoint.


Structure ◽  
2013 ◽  
Vol 21 (8) ◽  
pp. 1450-1459 ◽  
Author(s):  
Charles Chung Yun Leung ◽  
Luxin Sun ◽  
Zihua Gong ◽  
Michael Burkat ◽  
Ross Edwards ◽  
...  

2000 ◽  
Vol 113 (23) ◽  
pp. 4341-4350 ◽  
Author(s):  
A. Borgne ◽  
P. Nurse

Spd1p (for S phase delayed) is a cell cycle inhibitor in Schizosaccharomyces pombe. Spd1p overexpression blocks the onset of both S phase and mitosis. In this study, we have investigated the mechanisms by which Spd1p overexpression blocks cell cycle progression, focussing on the block over mitotic onset. High levels of Spd1p lead to an increase in Y15 phosphorylation of Cdc2p and we show that the block over G(2) requires the Wee1p kinase and is dependent on the rad and chk1/cds1 checkpoint genes. We propose that high levels of Spd1p in G(2) cells activate the DNA replication checkpoint control, which leads to a Wee1p-dependent increase of Cdc2p Y15 phosphorylation blocking onset of mitosis. The Spd1p block at S phase onset may act by interfering directly with DNA replication, and also activates the G(2)rad/hus checkpoint pathway to block mitosis.


Nature ◽  
10.1038/40439 ◽  
1997 ◽  
Vol 388 (6637) ◽  
pp. 93-97 ◽  
Author(s):  
Ody C. M. Sibon ◽  
Victoria A. Stevenson ◽  
William E. Theurkauf

2010 ◽  
Vol 37 (3) ◽  
pp. 438-446 ◽  
Author(s):  
Zihua Gong ◽  
Ja-Eun Kim ◽  
Charles Chung Yun Leung ◽  
J.N. Mark Glover ◽  
Junjie Chen

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