RNA polymerase II CTD interactome with 3′ processing and termination factors in fission yeast and its impact on phosphate homeostasis

作     者：Sanchez, Ana M. Shuman, Stewart Schwer, Beate 

作者机构：Weill Cornell Med Coll Dept Microbiol & Immunol New York NY 10065 USA Sloan Kettering Inst Mol Biol Program New York NY 10065 USA 

出 版 物：《PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA》 (美国国家科学院汇刊)

年 卷 期：2018年第115卷第45期

页      面：E10652-E10661页

核心收录：

学科分类：07[理学] 08[工学] 

基　　金：NIH [R01-GM52470  R35-GM126945] 

主　　题：Pol2 CTD code transcription termination synthetic lethality 

摘      要：The carboxy-terminal domain (CTD) code encrypted within the (YSPTSPS7)-S-1-P-2-T-3-S-4-P-5-S-6 heptad repeats of RNA polymerase II (Pol2) is deeply rooted in eukaryal biology. Key steps to deciphering the code are identifying the events in gene expression that are governed by individual letters and then defining a vocabulary of multiletter words and their meaning. Thr4 and Ser7 exert opposite effects on the fission yeast pho1 gene, expression of which is repressed under phosphate-replete conditions by transcription of an upstream flanking long noncoding RNA (lncRNA). Here we attribute the derepression of pho1 by a CTD-S7A mutation to precocious termination of lncRNA synthesis, an effect that is erased by mutations of cleavage-polyadenylation factor (CPF) subunits Ctf1, Ssu72, Ppn1, Swd22, and Dis2 and termination factor Rhn1. By contrast, a CTD-T4A mutation hyperrepresses pho1, as do CPF subunit and Rhn1 mutations, implying that T4A reduces lncRNA termination. Moreover, CTD-T4A is synthetically lethal with ppn1 Delta and swd22 Delta, signifying that Thr4 and the Ppn1 center dot Swd22 module play important, functionally redundant roles in promoting Pol2 termination. We find that Ppn1 and Swd22 become essential for viability when the CTD array is curtailed and that S7A overcomes the need for Ppn1 center dot Swd22 in the short CTD context. Mutational synergies highlight redundant essential functions of (i) Ppn1 center dot Swd22 and Rhn1, (ii) Ppn1 center dot Swd22 Delta and Ctf1, and (iii) Ssu72 and Dis2 phosphatases. CTD alleles Y1F, S2A, and T4A have overlapping synthetic lethalities with ppn1 Delta and swd22., suggesting that Tyr1-Ser2-Thr4 form a threeletter CTD word that abets termination, with Rhn1 being a likely reader of this word.