Dynamic interactions of high Cdt1 and geminin levels regulate S phase in early Xenopus embryos.
Dynamic interactions of high Cdt1 and geminin levels regulate S phase in early Xenopus embryos.
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DOI：
10.1242/dev.068676
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发表时间：
2012-01
期刊：
影响因子：
--
通讯作者：
Blow JJ
中科院分区：
文献类型：
--
作者：
Kisielewska J;Blow JJ
Cdt 1在授权DNA复制中起着关键作用。在后生动物的体细胞中，Cdt 1及其天然抑制剂geminin由于细胞周期依赖性蛋白水解而显示其蛋白水平的相互波动。在这里，我们表明，Cdt 1和geminin的蛋白质水平持续高在早期非洲爪蟾胚胎的快速细胞周期。Cdt 1和双生蛋白复合物的免疫沉淀与它们的细胞周期时空动力学一起强烈支持Cdt 1许可活动由与双生蛋白的周期性相互作用而不是其蛋白水解调节的假设。异位双生蛋白的过表达减慢，但既不阻止早期胚胎细胞周期，也不影响内源性双生蛋白水平;在囊胚中期转化后约3-4小时观察到明显的胚胎致死。然而，通过ΔCdt1_193-447（其缺乏许可活性和降解序列）功能性敲低geminin会导致受影响细胞中的细胞周期停滞和DNA损伤。这导致了处理后胚胎的后续发育缺陷。我们的研究结果清楚地表明，快速增殖的早期非洲爪蟾胚胎细胞能够调节复制许可的持续存在的高水平的许可蛋白依赖于Cdt 1和双生蛋白之间的相互作用在细胞周期中的变化，但不是他们的降解。
Cdt1 plays a key role in licensing DNA for replication. In the somatic cells of metazoans, both Cdt1 and its natural inhibitor geminin show reciprocal fluctuations in their protein levels due to cell cycle-dependent proteolysis. Here, we show that the protein levels of Cdt1 and geminin are persistently high during the rapid cell cycles of the early Xenopus embryo. Immunoprecipitation of Cdt1 and geminin complexes together with their cell cycle spatiotemporal dynamics strongly supports the hypothesis that Cdt1 licensing activity is regulated by periodic interaction with geminin rather than its proteolysis. Overexpression of ectopic geminin slows down, but neither arrests early embryonic cell cycles nor affects endogenous geminin levels; apparent embryonic lethality is observed around 3-4 hours after Mid Blastula Transition. However functional knockdown of geminin by ΔCdt1_193-447, which lacks licensing activity and degradation sequences, causes cell cycle arrest and DNA damage in affected cells. This contributes to subsequent developmental defects in treated embryos. Our results clearly show that rapidly proliferating early Xenopus embryonic cells are able to regulate replication licensing in the persistent presence of high levels of licensing proteins relying on changing interactions between Cdt1 and geminin during the cell cycle, but not their degradation.
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影响因子：
4.8
作者：
Hu, J;Xiong, Y
通讯作者：
Xiong, Y
影响因子：
4.3
作者：
Bulavin, Dmitry V.;Demidenko, Zoya N.;Fornace, Albert J., Jr.
通讯作者：
Fornace, Albert J., Jr.
影响因子：
64.8
作者：
Del Bene, F;Tessmar-Raible, K;Wittbrodt, J
通讯作者：
Wittbrodt, J
DOI：
10.1073/pnas.0911500106
发表时间：
2009-12-01
影响因子：
11.1
作者：
Evrin, Cecile;Clarke, Pippa;Speck, Christian
通讯作者：
Speck, Christian
影响因子：
2.7
作者：
Clute, P;Masui, Y
通讯作者：
Masui, Y