Swi5 controls a novel wave of cyclin synthesis in late mitosis
Swi5 controls a novel wave of cyclin synthesis in late mitosis
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DOI：
10.1091/mbc.9.4.945
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发表时间：
1998-04-01
影响因子：
3.3
通讯作者：
Johnston, LH
中科院分区：
文献类型：
--
作者：
Aerne, BL;Johnson, AL;Johnston, LH
我们以前已经证明，在有丝分裂晚期，Swi5转录因子调节SIC1 CDK抑制物的表达。这表明Swi5可能控制着其他在结束有丝分裂过程中起作用的基因。我们在启动子中发现了一个带有Swi5结合位点的基因，该基因编码一个与Pcl2高度同源的蛋白，Pcl2是一种与CDK Pho85相关的周期蛋白样蛋白。这个名为PCL9的基因确实在M期晚期受Swi5的调控，Swi5是目前已知的细胞周期中唯一表达的细胞周期蛋白。Pcl9蛋白与依赖于Pho85的蛋白激酶活性有关，并且该蛋白是不稳定的，峰值出现在M期晚期。我们已经知道PCL2在G1期晚期表达，此外，我们还发现它在末期也受Swi5的调控。PCL2和PCL9在细胞周期的这一阶段的表达暗示了Pho85 CDK在有丝分裂结束时的作用。与此一致的是，在Pho85 Delta和SIC1、SWI5和SPO12缺失的菌株之间观察到了合成的相互作用。这些研究和其他研究支持M/G1转换是一个主要的细胞周期转变的概念。
We have shown previously that the Swi5 transcription factor regulates the expression of the SIC1 Cdk inhibitor in late mitosis. This suggests that Swi5 might control other genes with roles in ending mitosis. We identified a gene with a Swi5-binding site in the promoter that encoded a protein with high homology to Pcl2, a cyclin-like protein that associates with the Cdk Pho85. This gene, PCL9, is indeed regulated by Swi5 in late M phase, the only cyclin known to be expressed at this point in the cell cycle. The Pcl9 protein is associated with a Pho85-dependent protein kinase activity, and the protein is unstable with peak levels occurring in late M phase. PCL2 is already known to be expressed in late G1 and we find that, in addition, it is also regulated by Swi5 in telophase. The expression of PCL2 and PCL9 at this stage of the cell cycle implies a role for the Pho85 Cdk at the end of mitosis. Consistent with this a synthetic interaction was observed between pho85 Delta and strains deleted for SIC1, SWI5, and SPO12. These and other studies support the notion that the M/G1 switch is a major cell cycle transition.