title: Splice site strength-dependent activity and genetic buffering by poly-G runs.
abstract: 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 approximately 4-fold higher when adjacent to intermediate strength 5' splice sites (ss) than when adjacent to weak 5' ss, and approximately 1.3-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.
authors.affiliation: Department of Biology, Massachusetts Institute of Technology, Cambridge, Massachusetts, USA.
authors.forename: Xinshu
authors.initials: X
authors.lastname: Xiao
authors.forename: Zefeng
authors.initials: Z
authors.lastname: Wang
authors.forename: Minyoung
authors.initials: M
authors.lastname: Jang
authors.forename: Razvan
authors.initials: R
authors.lastname: Nutiu
authors.forename: Eric T
authors.initials: ET
authors.lastname: Wang
authors.forename: Christopher B
authors.initials: CB
authors.lastname: Burge
mesh_terms: D017398:Alternative Splicing; D020816:Amino Acid Motifs; D000818:Animals; D003432:Cross-Linking Reagents / Q000378:metabolism; D005091:Exons; D005821:Genetic Techniques; D034541:Heterogeneous-Nuclear Ribonucleoprotein Group F-H / Q000378:metabolism; D006801:Humans; D051379:Mice; D008957:Models, Genetic; D020411:Oligonucleotide Array Sequence Analysis; D011068:Poly G / Q000235:genetics*; D012322:RNA Precursors / Q000235:genetics; D012326:RNA Splicing; D012333:RNA, Messenger / Q000378:metabolism
chemical_list: D003432:Cross-Linking Reagents; D034541:Heterogeneous-Nuclear Ribonucleoprotein Group F-H; D012322:RNA Precursors; D012333:RNA, Messenger; D011068:Poly G