Niwa M, Berget S M
Marrs McClean Department of Biochemistry, Baylor College of Medicine, Houston, Texas 77030.
Genes Dev. 1991 Nov;5(11):2086-95. doi: 10.1101/gad.5.11.2086.
To investigate the relationship between splicing and polyadenylation during the production of vertebrate mRNAs, we examined the effect of mutation of a poly(A) site on splicing of upstream introns. Mutation of the AAUAAA polyadenylation consensus sequence inhibited in vitro splicing of an upstream intron. The magnitude of the depression depended on the magnesium concentration. Dependence of splicing on polyadenylation signals suggests the existence of interaction between polyadenylation and splicing factors. In multi-intron precursor RNAs containing duplicated splice sites, mutation of the poly(A) site inhibited removal of the last intron, but not the removal of introns farther upstream. Inhibition of removal of only the last intron suggests segmental recognition of multi-exon precursor RNAs and is consistent with previous suggestions that signals at both ends of an exon are required for effective splicing of an upstream intron.
为了研究脊椎动物mRNA产生过程中剪接与聚腺苷酸化之间的关系，我们检测了聚腺苷酸化位点突变对上游内含子剪接的影响。AAUAAA聚腺苷酸化共有序列的突变抑制了上游内含子的体外剪接。抑制程度取决于镁离子浓度。剪接对聚腺苷酸化信号的依赖性表明聚腺苷酸化因子与剪接因子之间存在相互作用。在含有重复剪接位点的多内含子前体RNA中，聚腺苷酸化位点的突变抑制了最后一个内含子的去除，但没有抑制更上游内含子的去除。仅抑制最后一个内含子的去除表明多外显子前体RNA存在分段识别，这与之前的观点一致，即外显子两端的信号是上游内含子有效剪接所必需的。
