An extragenic suppressor of prp24-1 defines genetic interaction between PRP24 and PRP21 gene products of Saccharomyces cerevisiae.
The temperature-sensitive prp24-1 mutation defines a gene product required for the first step in pre-mRNA splicing. PRP24 is probably a component of the U6 snRNP particle. We have applied genetic reversion analysis to identify proteins that interact with PRP24. Spontaneous revertants of the temperature-sensitive (ts)prp24-1 phenotype were analyzed for those that are due to extragenic suppression. We then extended our analysis to screen for suppressors that confer a distinct conditional phenotype. We have identified a temperature-sensitive extragenic suppressor, which was shown by genetic complementation analysis to be allelic to prp21-1. This suppressor, prp21-2, accumulates pre-mRNA at the non-permissive temperature, a phenotype similar to that of prp21-1. prp21-2 completely suppresses the splicing defect and restores in vivo levels of the U6 snRNA in the prp24-1 strain. Genetic analysis of the suppressor showed that prp21-2 is not a bypass suppressor of prp24-1. The suppression of prp24-1 by prp21-2 is gene specific and also allele specific with respect to both the loci. Genetic interactions with other components of the pre-spliceosome have also been studied. Our results indicate an interaction between PRP21, a component of the U2 snRNP, and PRP24, a component of the U6 snRNP. These results substantiate other data showing U2-U6 snRNA interactions.
Vaidya
V C
VC
Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, India.
Seshadri
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V
Vijayraghavan
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U
D000483:Alleles; D015152:Blotting, Northern; D003433:Crosses, Genetic; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism; D015966:Gene Expression Regulation, Fungal / Q000235:genetics; D005816:Genetic Complementation Test; D005838:Genotype; D008540:Meiosis / Q000235:genetics; D009154:Mutation / Q000235:genetics; D010641:Phenotype; D011003:Ploidies; D012322:RNA Precursors / Q000378:metabolism; D012326:RNA Splicing / Q000235:genetics*; D016601:RNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins; D017381:Spliceosomes / Q000378:metabolism; D013489:Suppression, Genetic / Q000235:genetics*
D005656:Fungal Proteins; C082350:PRP21 protein, S cerevisiae; D012322:RNA Precursors; D016601:RNA-Binding Proteins; D029701:Saccharomyces cerevisiae Proteins