TIF4631 AND TIF4632 - 2 YEAST GENES ENCODING THE HIGH-MOLECULAR-WEIGHT SUBUNITS OF THE CAP-BINDING PROTEIN COMPLEX (EUKARYOTIC INITIATION FACTOR-4F) CONTAIN AN RNA RECOGNITION MOTIF-LIKE SEQUENCE AND CARRY OUT AN ESSENTIAL FUNCTION
TIF4631 AND TIF4632 - 2 YEAST GENES ENCODING THE HIGH-MOLECULAR-WEIGHT SUBUNITS OF THE CAP-BINDING PROTEIN COMPLEX (EUKARYOTIC INITIATION FACTOR-4F) CONTAIN AN RNA RECOGNITION MOTIF-LIKE SEQUENCE AND CARRY OUT AN ESSENTIAL FUNCTION
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DOI：
10.1128/mcb.13.8.4860
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发表时间：
1993-08-01
影响因子：
5.3
通讯作者：
SONENBERG, N
中科院分区：
文献类型：
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作者：
GOYER, C;ALTMANN, M;SONENBERG, N
真核mrna的5'端被帽状结构m7GpppX阻断（其中X是任意核苷酸）。帽结构与帽结合蛋白复合物的相互作用是核糖体与mRNA有效结合所必需的。在酿酒酵母中，帽结合蛋白复合物是由两个亚基组成的异源二聚体，分子量为24 （eIF-4E, CDC33）和150 (p150) kDa。p150被认为是哺乳动物eIF-4F中p220成分的酵母同源物。在这篇报道中，我们描述了酵母基因TIF4631的分离，该基因编码p150，和一个密切相关的基因TIF4632。TIF4631和TIF4632在其羧基末端的320个氨基酸长度上整体上有53%的相同，80%的相同。Bo蛋白含有类似RNA识别基序和辅助结构域的序列，这些结构域是RNA结合蛋白大家族的特征。tif4631断裂的菌株表现出生长缓慢、冷敏感的表型，而TIF4632断裂的菌株在实验条件下没有表现出任何表型。双基因破坏可致死性，这表明这两个基因在功能上是同源的，并表明它们中至少有一个对生存至关重要。这些数据与假设的酵母eIF-4F的高分子量亚基在翻译中的关键作用一致。TIF4631、TIF4632与人类eIF-4F p220亚基的序列比较显示出显著的同源性。因此，我们克隆了两个哺乳动物p220的酵母同源物。
The 5' ends of eukaryotic mRNAs are blocked by a cap structure, m7GpppX (where X is any nucleotide). The interaction of the cap structure with a cap-binding protein complex is required for efficient ribosome binding to the mRNA. In Saccharomyces cerevisiae, the cap-binding protein complex is a heterodimer composed of two subunits with molecular masses of 24 (eIF-4E, CDC33) and 150 (p150) kDa. p150 is presumed to be the yeast homolog of the p220 component of mammalian eIF-4F. In this report, we describe the isolation of yeast gene TIF4631, which encodes p150, and a closely related gene, TIF4632. TIF4631 and TIF4632 are 53% identical overall and 80% identical over a 320-amino-acid stretch in their carboxy-terminal halves. Bo proteins contain sequences resembling the RNA recognition motif and auxiliary domains that are characteristic of a large family of RNA-binding proteins. tif4631-disrupted strains exhibited a slow-growth, cold-sensitive phenotype, while disruption of TIF4632 failed to show any phenotype under the conditions assayed. Double gene disruption engendered lethality, suggesting that the two genes are functionally homologous and demonstrating that at least one of them is essential for viability. These data are consistent with a critical role for the high-molecular-weight subunit of putative yeast eIF-4F in translation. Sequence comparison of TIF4631, TIF4632, and the human eIF-4F p220 subunit revealed significant stretches of homology. We have thus cloned two yeast homologs of mammalian p220.