Suppression of telomere capping defects of Saccharomyces cerevisiae yku70 and yku80 mutants by telomerase.
Suppression of telomere capping defects of Saccharomyces cerevisiae yku70 and yku80 mutants by telomerase.
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DOI：
10.1093/g3journal/jkab359
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发表时间：
2021-12-08
期刊：
影响因子：
--
通讯作者：
Lewis LK
中科院分区：
文献类型：
--
作者：
Holland CL;Sanderson BA;Titus JK;Weis MF;Riojas AM;Malczewskyj E;Wasko BM;Lewis LK
Ku复合物在真核细胞内具有多种功能，包括保护染色体DNA末端免受降解和融合事件的影响，端粒酶的募集和双链断裂（DSBs）的修复。酵母细胞中Ku复合物基因YKU70或YKU80的失活会产生端粒缩短和温度敏感生长的突变体。在本研究中，我们研究了端粒酶过表达抑制yku突变体温度敏感性的机制。通过过表达Est2逆转录酶和端粒酶TLC1 RNA模板亚基，而不表达Est1或Est3蛋白，可以恢复yku细胞的活力。过表达其他端粒酶和端粒相关蛋白（Cdc13、Stn1、Ten1、Rif1、Rif2、Sir3和Sir4）不抑制yku70细胞的生长缺陷。使用几种TLC1 RNA缺失衍生物和Est2酶突变体来评估抑制的机制特征。三种催化失活的逆转录酶突变体（Est2- d530a、Est2- d670a和Est2- d671a）的超生理水平与野生型Est2蛋白一样有效地抑制了活力的丧失，而不会诱导细胞衰老。蛋白质调节端粒长度的作用也被确定。研究结果支持了一种模型，即yku突变体中的染色体是通过一种不依赖复制的机制来稳定的，这种机制涉及保护性端粒帽结构的结构增强。
The Ku complex performs multiple functions inside eukaryotic cells, including protection of chromosomal DNA ends from degradation and fusion events, recruitment of telomerase, and repair of double-strand breaks (DSBs). Inactivation of Ku complex genes YKU70 or YKU80 in cells of the yeast Saccharomyces cerevisiae gives rise to mutants that exhibit shortened telomeres and temperature-sensitive growth. In this study, we have investigated the mechanism by which overexpression of telomerase suppresses the temperature sensitivity of yku mutants. Viability of yku cells was restored by overexpression of the Est2 reverse transcriptase and TLC1 RNA template subunits of telomerase, but not the Est1 or Est3 proteins. Overexpression of other telomerase- and telomere-associated proteins (Cdc13, Stn1, Ten1, Rif1, Rif2, Sir3, and Sir4) did not suppress the growth defects of yku70 cells. Mechanistic features of suppression were assessed using several TLC1 RNA deletion derivatives and Est2 enzyme mutants. Supraphysiological levels of three catalytically inactive reverse transcriptase mutants (Est2-D530A, Est2-D670A, and Est2-D671A) suppressed the loss of viability as efficiently as the wild-type Est2 protein, without inducing cell senescence. Roles of proteins regulating telomere length were also determined. The results support a model in which chromosomes in yku mutants are stabilized via a replication-independent mechanism involving structural reinforcement of protective telomere cap structures.
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影响因子：
4.5
作者：
Bonetti D;Clerici M;Anbalagan S;Martina M;Lucchini G;Longhese MP
通讯作者：
Longhese MP
影响因子：
3.8
作者：
Wasko BM;Holland CL;Resnick MA;Lewis LK
通讯作者：
Lewis LK
影响因子：
16.8
作者：
Fisher, TS;Taggart, AKP;Zakian, VA
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Zakian, VA
影响因子：
3.8
作者：
Becerra, Sandra C.;Thambugala, Hiranthi T.;Lewis, L. Kevin
通讯作者：
Lewis, L. Kevin
DOI：
10.1098/rstb.2003.1370
发表时间：
2004-01-29
影响因子：
6.3
作者：
Chan, SRWL;Blackburn, EH
通讯作者：
Blackburn, EH