CLB5 - A NOVEL B-CYCLIN FROM BUDDING YEAST WITH A ROLE IN S-PHASE
CLB5 - A NOVEL B-CYCLIN FROM BUDDING YEAST WITH A ROLE IN S-PHASE
复制标题
DOI：
10.1101/gad.6.9.1695
复制
发表时间：
1992-09-01
影响因子：
10.5
通讯作者：
CROSS, FR
中科院分区：
文献类型：
--
作者：
EPSTEIN, CB;CROSS, FR
芽殖酵母菌株具有三个 CLN 基因，其细胞周期蛋白同源性有限。细胞周期启动至少需要三者之一。酵母中已知有四种 B 细胞周期蛋白；其中两个已被证明在有丝分裂中发挥作用。我们发现了第五个 B 细胞周期蛋白基因，称为 CLB5，当将其克隆到 CEN 质粒上时，可以挽救所有三个 CLN 基因都被删除的菌株。 CLB5 转录本丰度在 G1 达到峰值，与 CLN2 转录本一致，但早于 CLB2 转录本。 CLB5 缺失单独或与其他 CLN 或 CLB 缺失结合不会导致致死性。然而，删除 CLB5 的菌株需要更多时间才能完成 S 期，这表明 CLB5 促进了 DNA 合成的某些步骤。 CLB5 是唯一一个缺失可延长 S 期的酵母细胞周期蛋白。 CLB5 也可能在促进 G1/S 转变中发挥一定作用，因为 cln1 cln2 菌株需要 CLN3 和 CLB5 才能在甘油培养基上存活，而 cln1,2,3- 菌株需要 CLB5 才能被果蝇 cdc2 基因拯救。结合 CLB5 过表达对 cln1,2,3 的拯救以及 CLB5 和 CLN2 的一致转录调节，这些观察结果表明 CLB5 和 CLN 基因之间存在部分功能冗余。
Budding yeast strains have three CLN genes, which have limited cyclin homology. At least one of the three is required for cell cycle START. Four B cyclins are known in yeast; two have been shown to function in mitosis. We have discovered a fifth B-cyclin gene, called CLB5, which when cloned on a CEN plasmid can rescue strains deleted for all three CLN genes. CLB5 transcript abundance peaks in G1, coincident with the CLN2 transcript but earlier than the CLB2 transcript. CLB5 deletion does not cause lethality, either alone or in combination with other CLN or CLB deletions. However, strains deleted for CLB5 require more time to complete S phase, suggesting that CLB5 promotes some step in DNA synthesis. CLB5 is the only yeast cyclin whose deletion lengthens S phase. CLB5 may also have some role in promoting the G1/S transition, because cln1 cln2 strains require both CLN3 and CLB5 for viability on glycerol media and cln1,2,3- strains require CLB5 for rescue by the Drosophila melanogaster cdc2 gene. In conjunction with cln1,2,3 rescue by CLB5 overexpression and the coincident transcriptional regulation of CLB5 and CLN2, these observations are suggestive of partial functional redundancy between CLB5 and CLN genes.