Vankan P, McGuigan C, Mattaj I W
European Molecular Biology Laboratory, Heidelberg, FRG.
EMBO J. 1990 Oct;9(10):3397-404. doi: 10.1002/j.1460-2075.1990.tb07541.x.
Structure-function relationships in the vertebrate U4-U6 snRNP have been analysed by assaying the ability of mutant RNAs to form U4-U6 snRNPs and to function in splicing complementation in Xenopus oocytes. The mutants define three categories of domain within the RNAs. First, domains which are not essential for splicing. These include regions of U6 which have previously been implicated in the capping and transport to the nucleus of U6 RNA as well as, less surprisingly, regions of U4 and U6 which have been poorly conserved in evolution. Second, domains whose mutation reduces U4-U6 snRNP assembly or stability. This group includes mutations in both the proposed U4-U6 interaction domain, and also, in the case of U6, in a highly conserve sequence flanking stem I of the interaction domain. These mutants are all defective in splicing. Third, regions not required for U4-U6 assembly, but required for splicing complementation. This category defines domains which are likely to be required for specific contacts with other components of the splicing machinery. Combinations of mutants in the U4 and U6 interaction domain are used to show that there are not only requirements for base complementarity but also for specific sequences in these regions.
通过检测突变RNA形成U4-U6 snRNP的能力以及在非洲爪蟾卵母细胞中进行剪接互补的功能，对脊椎动物U4-U6 snRNP中的结构-功能关系进行了分析。这些突变体在RNA中定义了三类结构域。第一类是对于剪接并非必需的结构域。这包括U6中先前被认为与U6 RNA的加帽和向细胞核转运有关的区域，以及在进化过程中保守性较差的U4和U6区域，这并不令人意外。第二类是其突变会降低U4-U6 snRNP组装或稳定性的结构域。这一组包括在假定的U4-U6相互作用结构域中的突变，以及就U6而言，在相互作用结构域茎I侧翼的一个高度保守序列中的突变。这些突变体在剪接方面均存在缺陷。第三类是U4-U6组装不需要但剪接互补需要的区域。这一类定义了可能与剪接机制的其他组分进行特定接触所必需的结构域。U4和U6相互作用结构域中的突变体组合用于表明，这些区域不仅需要碱基互补，还需要特定序列。
