一种新型的U1/U5相互作用表明，在mRNA剪接的早期步骤中，U1和U5小核RNA（snRNA）之间存在空间上的接近。
A novel U1/U5 interaction indicates proximity between U1 and U5 snRNAs during an early step of mRNA splicing.
作者信息
Ast G, Weiner A M
机构信息
Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, Connecticut 06520-8114, USA.
出版信息
RNA. 1997 Apr;3(4):371-81.
The five spliceosomal snRNAs (U1, U2, U4, U5, and U6) undergo an ordered sequence of conformational changes as mRNA splicing progresses. We have shown that an antisense RNA oligonucleotide complementary to U5 snRNA induces a novel U1/U4/U5 complex that may be a transitional stage in the displacement of U1 from the 5' splice site by U5. Here we identify a novel site-specific crosslink between the 5' end of U1 and the invariant loop of U5 snRNA. This crosslink can be induced in nuclear extract by an antisense oligonucleotide directed against U5 snRNA, but can also be detected during an early step of the splicing reaction in the absence of oligonucleotide. Our data indicate proximity between U1 and U5 snRNPs before the first catalytic step of splicing, and may suggest that U1 helps to direct U5 to the 5' splice site.
随着mRNA剪接的进行，五种剪接体snRNA（U1、U2、U4、U5和U6）会经历一系列有序的构象变化。我们已经表明，与U5 snRNA互补的反义RNA寡核苷酸会诱导形成一种新型的U1/U4/U5复合物，该复合物可能是U5将U1从5'剪接位点置换过程中的一个过渡阶段。在这里，我们鉴定出U1的5'末端与U5 snRNA的不变环之间存在一种新型的位点特异性交联。这种交联可以通过针对U5 snRNA的反义寡核苷酸在核提取物中诱导产生，但在没有寡核苷酸的剪接反应早期步骤中也能检测到。我们的数据表明在剪接的第一个催化步骤之前U1和U5 snRNP之间存在接近性，这可能表明U1有助于将U5引导至5'剪接位点。
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