A conditional U5 snRNA mutation affecting pre-mRNA splicing and nuclear pre-mRNA retention identifies SSD1/SRK1 as a general splicing mutant suppressor

作者：Luukkonen BGM; Seraphin B^*

来源：Nucleic Acids Research, 1999, 27(17): 3455-3465.

DOI：10.1093/nar/27.17.3455

A combination of point mutations disrupting both stem 1 and stem 2 of U5 snRNA (U5A1) was found to confer a thermosensitive phenotype in vivo, In a strain expressing U5AI, pre-mRNA splicing was blocked before the first step through an inability of the mutant U5 snRNA to efficiently associate with the U4/U6 di-snRNP. Formation of early splicing complexes was not affected in extracts prepared from U5 snRNA mutant cells, while the capacity of these extracts to splice a pre-mRNA in vitro was greatly diminished. In addition, significant levels of a translation product derived from intron containing pre-mRNAs could be detected in vivo. The SSD1/SRK1 gene was identified as a multi-copy suppressor of the U5A1 snRNA mutant. Single copy expression of SSD1/SRK1 was sufficient to suppress the thermosensitive phenotype, and high copy expression partially suppressed the splicing and U4/U6.U5 tri-snRNP assembly phenotypes, SSD1/SRK1 also suppressed thermosensitive mutations in the Prp18p and U1-70K proteins, while inhibiting growth of the cold sensitive U1-4U snRNA mutant at 30 degrees C. Thus we have identified SSD1/SRK1 as a general suppressor of splicing mutants.

• 出版日期1999-9-1