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Studies on the mechanisms for nucleocytoplasmic transport and localization of mRNAs using the temperature sensitive mutants in the fisson yeast

利用裂殖酵母温度敏感突变体研究 mRNA 的核质运输和定位机制

基本信息

批准号：
08458221
负责人：
TANI Tokio
金额：
$ 4.61万
依托单位：
KYUSHU UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
1996
资助国家：
日本
起止时间：
1996 至 1997
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-08458221/
关键词：
fission yeast mRNA transport mutant ubiquitin nucleus gene mRNA輸送転写因子 ATP GTP結合蛋白温度感受性変異

项目摘要

Nucleocytoplasmic transport of mRNA is one of the essential steps in the eukaryotic gene expression. However, a mechanism of mRNA transport is mostly unknown. To elucidate a molecular mechanism for mRNA export, we have screend a bank of mutants temperature sensitive for growth in fission yeast Schizosacccharomyces pombe by using in situ hybridization with an oligo dT probe that hybridizes to the poly A tail of mRNAs, and identified seven mutants that accumulate mRNA in the nuclei at the nonpermissive temperature. Those mutations are all recessive and fall into seven different groups designated as ptr1-7 (poly(A)^+ RNA tranport). By functional complementation using an S.pombe genomic library, we have cloned the genes complementing each mutation. Analyzes of the cloned genes revealed that ptr1^+, ptr2^+, ptr3^+, ptr4^+ and ptr6^+ encode the ubiquitin ligase E3-like protein, the guanine nucleotide exchange factor for Rna/TC4, ubiquitin activating enzyme E3, Cut1p required for the chromosome segregation, and the homologue for human TAFII55, respectively. ptr5^+ and ptr7^+ were found to encode novel proteins in S.pombe. These results suggest that the ubiquitination system plays an important role in the mRNA transport pathway, and that there might be a tight linkage between the mRNA transport and the other cellular events, such as the gene transcription and cell cycle progression

核质转运是真核基因表达中必不可少的步骤之一。然而，信使核糖核酸的转运机制大多还不清楚。为了阐明mRNA输出的分子机制，我们利用与mRNAs聚A尾部杂交的寡核苷酸DT探针进行原位杂交，筛选出裂殖酵母pombe中对生长温度敏感的突变体，并鉴定了7个在不允许的温度下在细胞核中积累mRNA的突变体。这些突变都是隐性的，分为七个不同的组，命名为ptr1-7(Poly(A)^+RNA Transport)。通过使用S.pombe基因组文库进行功能互补，我们已经克隆了补充每个突变的基因。对克隆的基因进行分析表明，ptr1^+、ptr2^+、ptr3^+、ptr4^+和ptr6^+分别编码泛素连接酶E3蛋白、RNA/TC4鸟嘌呤核苷酸交换因子、染色体分离所需的泛素激活酶E3、Cut1p以及人TAFII55的同源物。Ptr5^+和ptr7^+编码了庞氏链霉菌中的新蛋白。这些结果表明，泛素化系统在mRNAs的运输途径中起着重要的作用，mrna的运输可能与其他细胞事件，如基因转录和细胞周期进程之间存在紧密的联系。