Yang X, Bani M R, Lu S J, Rowan S, Ben-David Y, Chabot B
Département de Microbiologie, Faculté de Médecine, Université de Sherbrooke, PQ Canada.
Proc Natl Acad Sci U S A. 1994 Jul 19;91(15):6924-8. doi: 10.1073/pnas.91.15.6924.
Recent in vitro results suggest that the heterogeneous nuclear ribonucleoparticle (hnRNP) A1 protein modulates alternative splicing by favoring distal 5' splice site (5'SS) selection and exon skipping. We used a mouse erythroleukemia (MEL) cell line (CB3C7) deficient in the expression of hnRNP A1 to test whether variations in hnRNP A1 and AlB protein levels affected alternative splicing in vivo. In contrast to A1-expressing MEL cell lines, CB3C7 cells preferentially selected the proximal 13S and 12S 5'SS on the adenovirus E1A pre-mRNA. Transiently expressing the A1 or A1B cDNA in CB3C7 cells shifted 5'SS selection toward the more distal 9S donor site. A1 protein synthesis was required for this effect since the expression of a mutated A1 cDNA did not affect 5'SS selection. These results demonstrate that in vivo variations in hnRNP A1 protein levels can influence 5'SS selection.
近期的体外实验结果表明，不均一核核糖核蛋白（hnRNP）A1蛋白通过促进远端5'剪接位点（5'SS）的选择和外显子跳跃来调节可变剪接。我们使用了一种缺乏hnRNP A1表达的小鼠红白血病（MEL）细胞系（CB3C7），以测试hnRNP A1和AlB蛋白水平的变化是否会在体内影响可变剪接。与表达A1的MEL细胞系相比，CB3C7细胞在腺病毒E1A前体mRNA上优先选择近端13S和12S 5'SS。在CB3C7细胞中瞬时表达A1或A1B cDNA会使5'SS选择向更远端的9S供体位点偏移。由于突变的A1 cDNA的表达不影响5'SS选择，因此这种效应需要A1蛋白的合成。这些结果表明，hnRNP A1蛋白水平的体内变化可影响5'SS选择。
