Tarun S Z, Sachs A B
Department of Molecular and Cell Biology, University of California at Berkeley 94720, USA.
Genes Dev. 1995 Dec 1;9(23):2997-3007. doi: 10.1101/gad.9.23.2997.
The mRNA poly(A) tail and its associated poly(A) binding protein (Pab1p) are ubiquitous in eukaryotes. The function of the poly(A) tail is to stabilize mRNA and to stimulate its translation. The development of a poly(A)- and cap-dependent yeast in vitro translation system has allowed us to understand how poly(A) stimulates translation. We find that Pab1p but not the cap binding protein eIF-4E is required for poly(A) tail-dependent translation, and that the Pab1p-poly(A) tail complex functions to recruit the 40S ribosomal subunit to the mRNA. These data introduce a new step into the pathway of translation initiation and merge the translational functions of the two ends of mRNA.
信使核糖核酸（mRNA）的聚腺苷酸（poly(A)）尾巴及其相关的聚腺苷酸结合蛋白（Pab1p）在真核生物中普遍存在。聚腺苷酸尾巴的功能是稳定mRNA并刺激其翻译。一种依赖聚腺苷酸和帽子结构的酵母体外翻译系统的开发，使我们得以了解聚腺苷酸是如何刺激翻译的。我们发现，聚腺苷酸尾巴依赖的翻译需要Pab1p而不是帽子结合蛋白eIF-4E，并且Pab1p-聚腺苷酸尾巴复合物的功能是将40S核糖体亚基招募到mRNA上。这些数据为翻译起始途径引入了一个新步骤，并融合了mRNA两端的翻译功能。
