A SACCHAROMYCES-CEREVISIAE HOMOLOG OF MAMMALIAN TRANSLATION INITIATION FACTOR-4B CONTRIBUTES TO RNA HELICASE ACTIVITY
A SACCHAROMYCES-CEREVISIAE HOMOLOG OF MAMMALIAN TRANSLATION INITIATION FACTOR-4B CONTRIBUTES TO RNA HELICASE ACTIVITY
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DOI：
10.1002/j.1460-2075.1993.tb06077.x
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发表时间：
1993-10-01
期刊：
影响因子：
11.4
通讯作者：
TRACHSEL, H
中科院分区：
文献类型：
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作者：
ALTMANN, M;MULLER, PP;TRACHSEL, H
克隆了酿酒酵母TIF 3基因并测序。推导的氨基酸序列与哺乳动物翻译起始因子eIF-4 B的序列有26%的同源性。TIF 3基因对生长不是必需的;然而，其破坏导致生长缓慢和冷敏感表型。与野生型提取物相比，来自TIF 3基因破坏菌株的提取物中的总酵母RNA的体外翻译减少。翻译缺陷在较低温度下更明显，并且可以通过添加野生型提取物或哺乳动物eIF-4 B而不是通过添加突变体提取物来校正。在TIF 3基因破坏的菌株中，在5'前导区具有不同程度的RNA二级结构的β-半乳糖苷酶报告mRNA的体内翻译显示优先抑制具有更稳定二级结构的mRNA的翻译。这表明Tif 3蛋白是RNA解旋酶或有助于体内RNA解旋酶活性。
The TIF3 gene of Saccharomyces cerevisiae was cloned and sequenced. The deduced amino acid sequence shows 26% identity with the sequence of mammalian translation initiation factor eIF-4B. The TIF3 gene is not essential for growth; however, its disruption results in a slow growth and cold-sensitive phenotype. In vitro translation of total yeast RNA in an extract from a TIF3 gene-disrupted strain is reduced compared with a wild-type extract. The translational defect is more pronounced at lower temperatures and can be corrected by the addition of wild-type extract or mammalian eIF-4B, but not by addition of mutant extract. In vivo translation of beta-galactosidase reporter mRNA with varying degree of RNA secondary structure in the 5' leader region in a TIF3 gene-disrupted strain shows preferential inhibition of translation of mRNA with more stable secondary structure. This indicates that Tif3 protein is an RNA helicase or contributes to RNA helicase activity in vivo.