Mutagenesis of the yeast gene PRP8 reveals domains governing the specificity and fidelity of 3{prime} splice site selection
- Univ. of California, San Francisco, CA (United States); and others
PRP8 encodes a highly conserved U5 snRNP protein required for spliceosome assembly and later steps of pre-mRNA splicing. We recently identified a novel allele, prp8-101, that specifically impairs recognition of the uridine tract that precedes most yeast 3{prime} slice sites. We carried out extensive mutagenesis of the gene and selected for new alleles that confer a phenotype similar to that of prp8-101. The strongest alleles cause changes in one of two amino acids in the C-terminal portion of the protein. We also identified a second class of PRP8 mutant that affects the fidelity of 3{prime} splice site utilization. These alleles suppress point mutations in the PyAG motif at the 3{prime} splice site and do not alter uridine tract recognition. The strongest of these alleles map to a region directly upstream of the prp8-101-like mutations. These new PRP8 alleles define two separable functions of Prp8p, required for specificity of 3{prime} splice site selection and fidelity of 3{prime} splice site utilization, respectively. Taken together with other recent biochemical and genetic data, our results suggest that Prp8p plays a functional role at the active site of the spliceosome during the second catalytic step of splicing. 43 refs., 7 figs., 7 tabs.
- OSTI ID:
- 543012
- Journal Information:
- Genetics, Journal Name: Genetics Journal Issue: 2 Vol. 143; ISSN GENTAE; ISSN 0016-6731
- Country of Publication:
- United States
- Language:
- English
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