The CRL2LRR-1 ubiquitin ligase regulates cell cycle progression during C. elegans development
The CRL2LRR-1 ubiquitin ligase regulates cell cycle progression during C. elegans development
复制标题
DOI：
10.1242/dev.054866
复制
发表时间：
2010-11-15
期刊：
影响因子：
4.6
通讯作者：
Pintard, Lionel
中科院分区：
文献类型：
--
作者：
Merlet, Jorge;Burger, Julien;Pintard, Lionel
在发育背景下调节细胞周期进程的分子机制知之甚少。在这里，我们表明，富含亮氨酸的重复蛋白LRR-1促进细胞周期进程在C。线虫的发育，无论是在生殖系和早期胚胎。我们的研究结果表明，LRR-1作为Cullin 2-RING E3连接酶复合物（CRL 2（LRR-1））的核底物识别亚基，确保DNA复制的完整性。LRR-1含有一个典型的BC/Cul-2盒，并以BC/Cul-2盒依赖性方式在体外和体内结合CRL 2组分。lrr-1功能的丧失导致生殖细胞系有丝分裂区域的细胞周期停滞，从而由于生殖细胞的耗尽而导致不育。DNA复制检查点信号传导组分ATL-1和CHK-1的失活抑制这种细胞周期停滞，并且显著地恢复lrr-1突变体生育力。同样，在早期胚胎中，lrr-1功能的丧失诱导CHK-1磷酸化和P谱系分裂中的严重细胞周期延迟，导致胚胎死亡。检查点激活在lrr-1突变体中不是组成性的，而是由DNA损伤诱导的，这可能是由于基因组的某些区域的再复制引起的，如单链DNA复制蛋白A（ssDNA-RPA-1）核灶的积累和lrr-1和lrr-1; atl-1双突变体中生殖细胞倍性的增加分别所证明的。总的来说，这些观察结果突出了CRL 2（LRR-1）复合物在基因组稳定性中的关键功能，通过维持C. elegans发育
The molecular mechanisms that regulate cell cycle progression in a developmental context are poorly understood. Here, we show that the leucine-rich repeat protein LRR-1 promotes cell cycle progression during C. elegans development, both in the germ line and in the early embryo. Our results indicate that LRR-1 acts as a nuclear substrate-recognition subunit of a Cullin 2-RING E3 ligase complex (CRL2(LRR-1)), which ensures DNA replication integrity. LRR-1 contains a typical BC/Cul-2 box and binds CRL2 components in vitro and in vivo in a BC/Cul-2 box-dependent manner. Loss of lrr-1 function causes cell cycle arrest in the mitotic region of the germ line, resulting in sterility due to the depletion of germ cells. Inactivation of the DNA replication checkpoint signaling components ATL-1 and CHK-1 suppresses this cell cycle arrest and, remarkably, restores lrr-1 mutant fertility. Likewise, in the early embryo, loss of lrr-1 function induces CHK-1 phosphorylation and a severe cell cycle delay in P lineage division, causing embryonic lethality. Checkpoint activation is not constitutive in lrr-1 mutants but is induced by DNA damage, which may arise due to re-replication of some regions of the genome as evidenced by the accumulation of single-stranded DNA-replication protein A (ssDNA-RPA-1) nuclear foci and the increase in germ cell ploidy in lrr-1 and lrr-1; atl-1 double mutants, respectively. Collectively, these observations highlight a crucial function of the CRL2(LRR-1) complex in genome stability via maintenance of DNA replication integrity during C. elegans development.