Roiha H, Shuster E O, Brow D A, Guthrie C
Department of Biochemistry and Biophysics, University of California, San Francisco 94143.
Gene. 1989 Oct 15;82(1):137-44. doi: 10.1016/0378-1119(89)90038-3.
Homologues of each of the five metazoan snRNAs required for pre-mRNA splicing have recently been identified in the budding yeast Saccharomyces cerevisiae on the basis of shared structural elements and evidence of similar roles during splicing. However, the spliceosomal snRNAs in this yeast are up to six times larger than their mammalian counterparts, suggesting that they may perform additional, perhaps species-specific, functions in the pre-mRNA processing pathway. We have undertaken a survey of 23 other budding yeasts to determine whether increased snRNA size is unique to Sacch. cerevisiae and, if not, to look for common structural motifs among homologous snRNAs. Our studies reveal that the spliceosomal snRNAs exhibit a surprising degree of size variation among these species. Furthermore, partial sequence analysis has identified a specific domain in the U6 snRNA which accounts for the observed size polymorphisms.
最近，基于共同的结构元件以及剪接过程中类似作用的证据，在芽殖酵母酿酒酵母中鉴定出了前体mRNA剪接所需的五种后生动物小核RNA（snRNA）中的每一种的同源物。然而，这种酵母中的剪接体snRNA比其哺乳动物对应物大六倍，这表明它们可能在前体mRNA加工途径中执行额外的、也许是物种特异性的功能。我们对另外23种芽殖酵母进行了一项调查，以确定snRNA大小增加是否是酿酒酵母特有的，如果不是，则寻找同源snRNA之间的共同结构基序。我们的研究表明，剪接体snRNA在这些物种中表现出惊人程度的大小变异。此外，部分序列分析在U6 snRNA中鉴定出一个特定结构域，该结构域解释了观察到的大小多态性。
