THE PRODUCTS OF THE SUP45 (ERF1) AND SUP35 GENES INTERACT TO MEDIATE TRANSLATION TERMINATION IN SACCHAROMYCES-CEREVISIAE
THE PRODUCTS OF THE SUP45 (ERF1) AND SUP35 GENES INTERACT TO MEDIATE TRANSLATION TERMINATION IN SACCHAROMYCES-CEREVISIAE
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DOI：
10.1002/j.1460-2075.1995.tb00111.x
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发表时间：
1995-09-01
期刊：
影响因子：
11.4
通讯作者：
TUITE, MF
中科院分区：
文献类型：
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作者：
STANSFIELD, I;JONES, KM;TUITE, MF
酵母SUP45基因的产物（Sup45p）与爪蟾真核生物释放因子1 （eRF1）高度同源，在体外具有释放因子活性。我们使用双杂交系统表明，在酿酒酵母中，Sup45p和SUP35基因的产物（Sup35p）在体内相互作用。用（His）(6)标记的Sup45p c末端特异性地从细胞裂解液中沉淀Sup35p的能力在体外证实了这种相互作用。虽然单独过表达SUP45或SUP35基因都不会降低密码子特异性tRNA无义抑制的效率，但在含有无义抑制tRNA的菌株中同时过表达SUP35和SUP45基因会产生抗抑制表型。这些数据与Sup35p和Sup45p形成具有释放因子性质的复合物一致。此外，过表达爪蟾或人类eRF1 （SUP45）基因也导致抗抑制，只有当该菌株也过表达酵母SUP35基因。抗抑制是一种与原核生物和线粒体释放因子过表达相关的特征性表型。我们认为，Sup45p和Sup35p相互作用在酵母中形成一个释放因子复合物，而Sup35p在其c端结构域具有GTP结合序列基序，提供GTP水解活性，这是真核生物翻译终止反应的证明要求。
The product of the yeast SUP45 gene (Sup45p) is highly homologous to the Xenopus eukaryote release factor 1 (eRF1), which has release factor activity in vitro. We show using the two-hybrid system, that in Saccharomyces cerevisiae Sup45p and the product of the SUP35 gene (Sup35p) interact in vivo. The ability of Sup45p C-terminally tagged with (His)(6) to specifically precipitate Sup35p from a cell lysate was used to confirm this interaction in vitro. Although overexpression of either the SUP45 or SUP35 genes alone did not reduce the efficiency of codon-specific tRNA nonsense suppression, the simultaneous overexpression of both the SUP35 and SUP45 genes in nonsense suppressor tRNA-containing strains produced an antisuppressor phenotype. These data are consistent with Sup35p and Sup45p forming a complex with release factor properties. Furthermore, overexpression of either Xenopus or human eRF1 (SUP45) genes also resulted in antisuppression only if that strain was also overexpressing the yeast SUP35 gene. Antisuppression is a characteristic phenotype associated with overexpression of both prokaryote and mitochondrial release factors. We propose that Sup45p and Sup35p interact to form a release factor complex in yeast and that Sup35p, which has GTP binding sequence motifs in its C-terminal domain, provides the GTP hydrolytic activity which is a demonstrated requirement of the eukaryote translation termination reaction.