Chromosome stability and cellular senescence in yeast aging gene project

酵母衰老基因项目中的染色体稳定性和细胞衰老

基本信息

批准号：
10832006
负责人：
KIKUCHI Akihiko
金额：
$ 2.18万
依托单位：
NAGOYA University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1998
资助国家：
日本
起止时间：
1998 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-10832006/
关键词：
yeast aging heterochromatin nucleolus HTR1 SGS1 SIR DNA topoisomerases 酵母老化 UTH4 エージング・アッセイフロキシン MCS1 SSD1 テロメア GFPたんぱく

项目摘要

1 : Aging mechanism by yeast HTR1 geneThe products of two genes, HTR1 and SGS1 are suggested to involve in the cellular aging process in yeast. We constructed a double mutant and found that two genes were epistatic. The fusion product of HTR1p with GFP was localized in the cytoplasm. The deletion of HTR1 gene conferred the ultra sensitivity to hydroxyurea, and this sensitive phenotype was rescued by one of the multi copy suppressor of htr1 mutant. Since this suppressor gene product was shown as a corepressor particularly for the genes in heterochromatin region associated with SIR complex, the senescence signal must be transmitted from HTR1 to SIR and finally to the genes in heterochromatin.2 : Function of SGS1 geneThe product of another aging gene SGS1 was shown to interact with DNA topoisomerases. To visualize the alteration of chromosome structure and the extent to cellular senescence, we marked various fragments of DNA topoisomerases with GFP. Among these fusion product, some showed strong affinity to nucleolus, rather than to chromosomes. The genetical meaning of this observation is yet to be investigated, but we got very interesting clue to understand nucleolus function in aging process in relation to DNA topoisomerases.

图1：酵母HTR1基因的衰老机制HTR1和SGS1这两个基因的产物被认为参与酵母的细胞衰老过程。我们构建了一个双突变体，发现两个基因是上位的。 HTR1p 与 GFP 的融合产物定位于细胞质中。 HTR1基因的缺失赋予了对羟基脲的超敏感性，并且这种敏感表型被htr1突变体的多拷贝抑制子之一拯救。由于该抑制基因产物被证明是一种辅抑制因子，特别是对于与 SIR 复合物相关的异染色质区域中的基因，衰老信号必须从 HTR1 传递到 SIR，最后传递到异染色质中的基因。 2：SGS1 基因的功能另一种衰老的产物基因 SGS1 被证明与 DNA 拓扑异构酶相互作用。为了可视化染色体结构的改变和细胞衰老的程度，我们用 GFP 标记了 DNA 拓扑异构酶的各种片段。在这些融合产物中，一些融合产物对核仁而非染色体表现出很强的亲和力。这一观察结果的遗传意义还有待研究，但我们得到了非常有趣的线索来了解衰老过程中与 DNA 拓扑异构酶相关的核仁功能。