COMPARISON OF THE SACCHAROMYCES-CEREVISIAE G1 CYCLINS - CLN3 MAY BE AN UPSTREAM ACTIVATOR OF CLN1, CLN2 AND OTHER CYCLINS
COMPARISON OF THE SACCHAROMYCES-CEREVISIAE G1 CYCLINS - CLN3 MAY BE AN UPSTREAM ACTIVATOR OF CLN1, CLN2 AND OTHER CYCLINS
复制标题
DOI：
10.1002/j.1460-2075.1993.tb05845.x
复制
发表时间：
1993-05-01
期刊：
影响因子：
11.4
通讯作者：
FUTCHER, B
中科院分区：
文献类型：
--
作者：
TYERS, M;TOKIWA, G;FUTCHER, B
在芽殖酵母酿酒酵母（Saccharomyces cerevisiae）中，G1期细胞周期蛋白Cln 1、Cln 2和Cln 3通过激活Cdc28蛋白激酶来调节进入细胞周期（Start）。我们发现，Cln3是一种比Cln1或Cln2更罕见的蛋白质，并且具有更弱的相关组蛋白H1激酶活性。与Cln 1和Cln 2不同，Cln 3不受细胞周期的显著调节，也不受交配信息素诱导的G1期阻滞的下调。在G1期早期，CLN3表达的人工爆发加速了启动，并迅速诱导了至少五种其他细胞周期蛋白基因（CLN1，CLN2，HCS26，ORFD和CLB5）和细胞周期特异性转录因子SWI4。在类似的实验中，在激活Start时，CLN1的效率低于CLN3。引人注目的是，HCS26、ORFD和CLB5的表达依赖于cln1 cln2菌株中的CLN3，这可能解释了为什么CLN3在不存在CLN1和CLN2的情况下是必需的。为了解释Cln 3激活Start的强大能力，尽管其明显弱的生化活性，我们提出Cln 3可能是直接催化Start的G1细胞周期蛋白的上游激活剂。鉴于已知的细胞周期蛋白的大量，这样的细胞周期蛋白级联可能是一个共同的主题在细胞周期控制。
In the budding yeast Saccharomyces cerevisiae, the G1 cyclins Cln1, Cln2 and Cln3 regulate entry into the cell cycle (Start) by activating the Cdc28 protein kinase. We find that Cln3 is a much rarer protein than Cln1 or Cln2 and has a much weaker associated histone H1 kinase activity. Unlike Cln1 and Cln2, Cln3 is not significantly cell cycle regulated, nor is it down-regulated by mating pheromone-induced G1 arrest. An artificial burst of CLN3 expression early in G1 phase accelerates Start and rapidly induces at least five other cyclin genes (CLN1, CLN2, HCS26, ORFD and CLB5) and the cell cycle-specific transcription factor SWI4. In similar experiments, CLN1 is less efficient than CLN3 at activating Start. Strikingly, expression of HCS26, ORFD and CLB5 is dependent on CLN3 in a cln1 cln2 strain, possibly explaining why CLN3 is essential in the absence of CLN1 and CLN2. To explain the potent ability of Cln3 to activate Start, despite its apparently weak biochemical activity, we propose that Cln3 may be an upstream activator of the G1 cyclins which directly catalyze Start. Given the large number of known cyclins, such cyclin cascades may be a common theme in cell cycle control.