Regulation of the Ysh1 endonuclease of the mRNA cleavage/polyadenylation complex by ubiquitin-mediated degradation
Regulation of the Ysh1 endonuclease of the mRNA cleavage/polyadenylation complex by ubiquitin-mediated degradation
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DOI：
10.1080/15476286.2020.1724717
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发表时间：
2020-02
期刊：
影响因子：
4.1
通讯作者：
Susan D. Lee;Huiyun Liu;J. Graber;Daniel Heller-Trulli;Katarzyna Kaczmarek Michaels;Juan Francisco Cerezo;C. Moore
中科院分区：
文献类型：
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作者：
Susan D. Lee;Huiyun Liu;J. Graber;Daniel Heller-Trulli;Katarzyna Kaczmarek Michaels;Juan Francisco Cerezo;C. Moore
摘要酵母必需蛋白Ipa 1的突变已被证实会导致前体mRNA 3 ′端加工和生长的缺陷，但这些缺陷的机制尚不清楚。在这项研究中，我们发现ipa 1 -1突变导致Ysh 1（19-亚基mRNA切割/多聚腺苷酸化（C/P）复合物的进化上保守的核酸内切酶亚基）显著耗尽，但不会减少其他C/P亚基。YSH 1过表达挽救了ipa 1 -1突变体的生长和3 ′末端加工缺陷。在ipa 1 -1细胞中YSH 1 mRNA水平不变，蛋白酶体失活阻止Ysh 1丢失并导致泛素化Ysh 1积累。Ysh 1泛素化是由Ubc 4泛素结合酶介导的，而Mpe 1除了在C/P中起作用外，还是一种RING泛素连接酶。总之，Ipa 1通过控制C/P核酸内切酶的可用性来影响mRNA加工，并且可能代表可以快速部署以促进细胞反应重编程的调节机制。
ABSTRACT Mutation of the essential yeast protein Ipa1 has previously been demonstrated to cause defects in pre-mRNA 3ʹ end processing and growth, but the mechanism underlying these defects was not clear. In this study, we show that the ipa1-1 mutation causes a striking depletion of Ysh1, the evolutionarily conserved endonuclease subunit of the 19-subunit mRNA Cleavage/Polyadenylation (C/P) complex, but does not decrease other C/P subunits. YSH1 overexpression rescues both the growth and 3ʹ end processing defects of the ipa1-1 mutant. YSH1 mRNA level is unchanged in ipa1-1 cells, and proteasome inactivation prevents Ysh1 loss and causes accumulation of ubiquitinated Ysh1. Ysh1 ubiquitination is mediated by the Ubc4 ubiquitin-conjugating enzyme and Mpe1, which in addition to its function in C/P, is also a RING ubiquitin ligase. In summary, Ipa1 affects mRNA processing by controlling the availability of the C/P endonuclease and may represent a regulatory mechanism that could be rapidly deployed to facilitate reprogramming of cellular responses.