Regulation of cell cycle in the somatic cells

本项目包括三个部分，(1)从仓鼠BHK21细胞系中分离温度敏感（ts）突变体用于细胞生长，(2)鉴定突变体中的突变基因，(3)克隆突变基因的表征。我会复习每一部分。第1部分。在此之前，我已经建立了一种分离仓鼠BHK21细胞系的ts突变体的方法。然而，这些突变中的大多数在X染色体上有一个突变，在那里表达了单倍体剂量的基因。在这个项目中，我试图用一种叫苯甲酰的药物分离出常染色体的突变体。最后，我们分离出了属于不同互补群的ts突变体。第2部分。我们鉴定了仓鼠BHK21细胞系ts突变体的突变基因，它们分别是编码疱疹病毒增殖宿主细胞因子HCF、组氨酸- trna合成酶和赖氨酸- trna合成酶的基因。第3部分。我将回顾使用仓鼠BHK21细胞系的ts突变体克隆的每个基因。更多的CF：根据我们的发现，HCF被证实对宿主细胞增殖也是必不可少的。HCF基因缺陷突变体tsBN67在不允许温度下完成G1、S、G2和M期后在G0期停止。因此，该突变体将有助于在分子水平上表征G0期。氨酰基- trna合成酶：组氨酸和赖氨酸- trna合成酶缺陷突变体在非允许条件下迅速进入细胞凋亡，表明氨酰基- trna合成存在质量控制。DAD1：该基因的突变缺陷tsBN7在n -链糖基化上存在缺陷，该基因缺陷的小鼠因细胞凋亡而死亡。我们的研究结果表明，细胞凋亡与细胞周期之间存在密切的关系：1)我们鉴定了RanRP1/ yr1p、RanBP3/Yrb2、RanBP2/Yrb2、Dis3p、RanBPM和Mog1。RanBPM的发现表明Ran直接参与微管组装。2)我们发现双磷酸盐Cdc25B触发有丝分裂。由于Cdc25B的不稳定性，有丝分裂的进入被一种蛋白质合成抑制剂环己亚胺阻断。3)作为酿酒葡萄球菌RCC1和RanGAP同源突变体prp20和rna1-1的抑制基因，分离出GTR1和GTR2。这些是新的G蛋白，似乎对Ran循环起拮抗作用。少

This project is comprised of three parts, (1) the isolation of temperature-sensitive (ts) mutants for cell growth from hamster BHK21 cell line, (2) the identification of mutated genes in those mutants, and (3) the characterization of cloned mutated genes. I will review for each part. Part 1. Previously, I have established a method to isolate ts mutants of hamster BHK21 cell line. However, a majority of those mutants have a mutation in the X chromosome where a haploid dose of gene is expressed. In this project, I tried to isolate ts mutants of the autosome using a drug, benomyl. Finally, we isolated ts mutants belonging to a different complementation group. Part 2. We have identified mutated genes of ts mutants of hamster BHK21 cell line, which are genes encoding HCF (host cell factor for herpes virus proliferation), histidyl-tRNA synthetase and lysyl-tRNA synthetase, respectively. Part 3. I will review for each genes which have been cloned using ts mutants of hamster BHK21 cell line. H … More CF : Based on our finding, HCF was approved to be essential for host cell proliferation as well. The mutant defective in HCF gene, tsBN67, arrest in G0 phase after completion of the G1, S, G2 and M phase at the nonpermissive temperature. Thus, this mutant will be useful for characterizing the G0 phase at the molecular level. Aminoacyl-tRNA synthetase : mutants defective in histidyl- and lysyl-tRNA synthetases rapidly enter apoptosis under nonpermissive condition, indicating that there is a quality control for aminoacyl-tRNA synthesis. DAD1 : The mutant defective in this gene, tsBN7, has a defect in N-linked glycosylation, and mice defective in this gene die due to apoptosis. Our results indicate a tight relationship between apoptosis and cycle : 1) We have identified Ran-binding proteins, RanRP1/Yrb1p, RanBP3/Yrb2, RanBP2/Yrb2, Dis3p, RanBPM and Mog1. The finding of RanBPM introduced that Ran is directly involved in microtubule assembly. 2) We found that a dual phosphates, Cdc25B triggers mitosis. Due to the instability of Cdc25B, the entry of mitosis is blodked by cycloheximide, a protein synthesis inhibitor. 3) As a suppressor gene of prp20 and rna1-1, ts mutants of S. cerevisiae RCC1 and RanGAP homologue, we isolated GTR1 and GTR2. These are new G proteins which seems to function antagonistically to the Ran cycle. Less