Mutations in a peptidylprolyl-cis/trans-isomerase gene lead to a defect in 3′-end formation of a pre-mRNA in Saccharomyces cerevisiae
Mutations in a peptidylprolyl-cis/trans-isomerase gene lead to a defect in 3′-end formation of a pre-mRNA in Saccharomyces cerevisiae
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DOI：
10.1074/jbc.274.1.108
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发表时间：
1999-01-01
影响因子：
4.8
通讯作者：
Rahfeld, JU
中科院分区：
文献类型：
--
作者：
Hani, J;Schelbert, B;Rahfeld, JU
在旨在鉴定涉及芽殖酵母的mRNA 3 '-末端加工的反式作用因子的遗传筛选中，我们先前分离了两种温度敏感性突变体，其在质粒衍生的前mRNA的3'-末端形成中具有明显缺陷。令人惊讶的是，这两种突变体都被编码推定的肽基脯氨酰-顺式/反式异构酶（PPI酶）的必需基因ESS 1/PTF 1拯救（哈尼，J.，Stumpf，G.，和Domdey，H.（1995）FFBS Lett，365，198-202）。这种催化脯氨酸的N-末端的肽键的顺式/反式相互转化的酶被认为在蛋白质折叠或运输中起作用。在这里，我们报告，Ptf 1 p显示PPIase活性在体外，显示一个不寻常的底物特异性与磷酸化的丝氨酸和苏氨酸残基前脯氨酸的肽，这两个突变被发现导致在PPIase结构域内的高度保守的残基的氨基酸取代，导致PPIase活性的突变酶显着降低。我们的研究结果表明，一个迄今未知的参与PPIase在mRNA的3 '端形成的酿酒酵母。
In a genetic screen aimed at the identification of trans acting factors involved in mRNA 3'-end processing of budding yeast, we have previously isolated two temperature-sensitive mutants with an apparent defect in the 3'-end formation of a plasmid-derived pre-mRNA Surprisingly, both mutants were rescued by the essential gene ESS1/PTF1 that encoded a putative peptidylprolyl-cis/trans-isomerase (PPIase) (Hani, J., Stumpf, G., and Domdey, H. (1995) FFBS Lett, 365, 198-202), Such enzymes, which catalyze the cis/trans-interconversion of peptide bonds N-terminal of prolines, are suggested to play a role in protein folding or trafficking. Here we report that Ptf1p shows PPIase activity in vitro, displaying an unusual substrate specificity for peptides with phosphorylated serine and threonine residues preceding proline, Both mutations were found to result in amino acid substitutions of highly conserved residues within the PPIase domain, causing a marked decrease in PPIase activity of the mutant enzymes. Our results are suggestive of a so far unknown involvement of a PPIase in mRNA 3'-end formation in Saccharomyces cerevisiae.