Tarun S Z, Sachs A B
Department of Molecular and Cell Biology, University of California at Berkeley, 94720, USA.
EMBO J. 1996 Dec 16;15(24):7168-77.
Although the cap structure and the poly(A) tail are on opposite ends of the mRNA molecule, previous work has suggested that they interact to enhance translation and inhibit mRNA degradation. Here we present biochemical data that show that the proteins bound to the mRNA cap (eIF-4F) and poly(A) tail (Pab1p) are physically associated in extracts from the yeast Saccharomyces cerevisiae. Specifically, we find that Pab1p co-purifies and co-immunoprecipitates with the eIF-4G subunit of eIF-4F. The Pab1p binding site on the recombinant yeast eIF-4G protein Tif4632p was mapped to a 114-amino-acid region just proximal to its eIF-4E binding site. Pab1p only bound to this region when complexed to poly(A). These data support the model that the Pablp-poly(A) tail complex on mRNA can interact with the cap structure via eIF-4G.
尽管帽结构和聚（A）尾位于mRNA分子的两端，但先前的研究表明它们相互作用以增强翻译并抑制mRNA降解。在此，我们展示了生化数据，这些数据表明与mRNA帽结合的蛋白质（eIF-4F）和聚（A）尾（Pab1p）在酿酒酵母提取物中存在物理关联。具体而言，我们发现Pab1p与eIF-4F的eIF-4G亚基共同纯化并共同免疫沉淀。重组酵母eIF-4G蛋白Tif4632p上的Pab1p结合位点被定位到其eIF-4E结合位点近端的一个114个氨基酸的区域。Pab1p只有在与聚（A）复合时才会结合到该区域。这些数据支持了mRNA上的Pablp-聚（A）尾复合物可以通过eIF-4G与帽结构相互作用的模型。
