Portman D S, O'Connor J P, Dreyfuss G
Howard Hughes Medical Institute and Department of Biochemistry and Biophysics, University of Pennsylvania School of Medicine, Philadelphia 19104-6148, USA.
RNA. 1997 May;3(5):527-37.
The complexity of eukaryotic mRNA processing suggests a need for certain factors, called RNA chaperones, that can modulate RNA secondary structure as well as the interactions between pre-mRNA and trans-acting components. To identify factors that may fulfill this role in the yeast Saccharomyces cerevisiae, we fractionated whole-cell extracts and assayed for activity that could facilitate a specific RNA-RNA annealing reaction. We detected one strong RNA annealing activity and purified it to homogeneity. This previously undescribed factor, Yra1p, is localized to the nucleus; its sequence contains one RNP-motif RNA-binding domain. The YRA1 gene contains a 766-nt intron, the second-largest identified in this organism, and Yra1p serves an essential, nonredundant function. Taken together, our findings indicate that Yra1p is likely to have an important role in S. cerevisiae nuclear pre-mRNA metabolism.
真核生物信使核糖核酸（mRNA）加工过程的复杂性表明需要某些被称为RNA伴侣的因子，这些因子能够调节RNA二级结构以及前体mRNA与反式作用成分之间的相互作用。为了鉴定在酿酒酵母中可能发挥这一作用的因子，我们对全细胞提取物进行了分级分离，并检测了能够促进特定RNA-RNA退火反应的活性。我们检测到一种强烈的RNA退火活性，并将其纯化至同质。这个以前未被描述的因子Yra1p定位于细胞核；其序列包含一个核糖核蛋白基序（RNP-motif）RNA结合结构域。YRA1基因含有一个766个核苷酸的内含子，是该生物体中已鉴定出的第二大内含子，并且Yra1p发挥着必不可少的、非冗余的功能。综合来看，我们的研究结果表明Yra1p可能在酿酒酵母细胞核前体mRNA代谢中发挥重要作用。
