Brys A, Schwer B
Department of Biochemistry, University of Medicine and Dentistry of New Jersey, Robert Wood Johnson Medical School, Piscataway 08854, USA.
RNA. 1996 Jul;2(7):707-17.
Yeast pre-mRNA splicing factors SLU7 and PRP16 are required for cleavage of the 3' splice site and exon ligation in vitro. Using natural and model precursor RNAs, we found that SLU7 is dispensable for splicing of RNAs in which the 3' splice site is in close proximity to the branchpoint. SLU7 is only required when the interval between the branchpoint and the 3' splice site is greater than 7 nt. In contrast, PRP16 is essential for splicing of all pre-mRNAs tested. Immunoprecipitation of the products of step 1 by anti-SLU7 antibodies demonstrates that SLU7 is a component of the spliceosome. Recruitment of SLU7 to the spliceosome is greatly enhanced by prior addition of PRP16. PRP16 is liberated from the spliceosome after completion of step 2, whereas SLU7 remains bound to the excised intron and spliced mature RNA until the spliceosome disassembles, in a reaction that requires ATP.
酵母前体mRNA剪接因子SLU7和PRP16是体外3'剪接位点切割和外显子连接所必需的。使用天然和模型前体RNA，我们发现对于3'剪接位点紧邻分支点的RNA剪接，SLU7是可有可无的。只有当分支点与3'剪接位点之间的间隔大于7个核苷酸时，SLU7才是必需的。相比之下，PRP16对于所有测试的前体mRNA的剪接都是必不可少的。用抗SLU7抗体对步骤1的产物进行免疫沉淀表明，SLU7是剪接体的一个组成部分。通过预先添加PRP16，SLU7向剪接体的募集大大增强。在步骤2完成后，PRP16从剪接体中释放出来，而SLU7则一直与切除的内含子和剪接成熟的RNA结合，直到剪接体解体，这一反应需要ATP。
