Splice site strength-dependent activity and genetic buffering by poly-G runs

• Main Authors: Xiao, Xinshu (Contributor), Wang, Zefeng (Contributor), Jang, Minyoung (Contributor), Nutiu, Razvan (Contributor), Wang, Eric T (Author), Burge, Christopher B (Author)
• Other Authors: Whitaker College of Health Sciences and Technology (Contributor), Massachusetts Institute of Technology. Department of Biology (Contributor), Burge, Christopher B. (Contributor), Wang, Eric T. (Contributor)
• Format: Article
• Language: English
• Published: Nature Publishing Group, 2011-10-25T13:49:55Z.
• Subjects: Article
• Online Access: Get fulltext

 Pre-mRNA splicing is regulated through the combinatorial activity of RNA motifs, including splice sites and splicing regulatory elements. Here we show that the activity of the G-run (polyguanine sequence) class of splicing enhancer elements is approx4-fold higher when adjacent to intermediate strength 5' splice sites (ss) than when adjacent to weak 5' ss, and approx1.3-fold higher relative to strong 5' ss. We observed this dependence on 5' ss strength in both splicing reporters and in global microarray and mRNA-Seq analyses of splicing changes following RNA interference against heterogeneous nuclear ribonucleoprotein (hnRNP) H, which cross-linked to G-runs adjacent to many regulated exons. An exon's responsiveness to changes in hnRNP H levels therefore depends in a complex way on G-run abundance and 5' ss strength. This pattern of activity enables G-runs and hnRNP H to buffer the effects of 5' ss mutations, augmenting both the frequency of 5' ss polymorphism and the evolution of new splicing patterns. Certain other splicing factors may function similarly.