A Genetic Screen for Suppressors of a Mutated 5 ' Splice Site Identifies Factors Associated With Later Steps of Spliceosome Assembly

作者：Dassah MaryAnn; Patzek Sophie; Hunt Valerie M; Medina Pedro E; Zahler Alan M^*

来源：Genetics, 2009, 182(3): 725-734.

DOI：10.1534/genetics.109.103473

Many alleles of human disease genes have mutations within splicing consensus sequences that activate cryptic splice sites. In Caenorhabditis elegans, the unc-73(e936) allele has a G-to-U mutation at the first base of the intron downstream of exon 15, which results in all uncoordinated phenotype. This Imitation triggers cryptic splicing at the -1 and 23 positions and retains some residual splicing at the mutated wild-type (wt) Position. We previously demonstrated that. a initiation in sup-39, a U1 snRNA gene, suppresses e936 by increasing splicing at the wt splice site. We report here the results of a suppressor screen in which we identify three proteins that function in cryptic splice site choice. Loss-of-function mutations in the nonessential splicing factor smu-2 suppress e936 uncoordination through changes in splicing. SMU-2 binds SMU-1, and smu-1(RNAi) also leads to suppression of e936 A dominant mutation in the conserved G-terminal domain of the C. elegans homolog of the human tri-snRNP 27K protein, which we have named SNRP-27, suppresses e936 uncoordination through changes in splicing. We propose that SMU-2, SMU-1, and SNRP-27 contribute to the fidelity of splice site choice after the initial identification of 5' splice sites by U1 snRNP.

• 出版日期2009-7