Molecular and General Genetics MGG

, Volume 250, Issue 3, pp 267–276

An extragenic suppressor ofprp24-1 defines genetic interaction betweenPRP24 andPRP21 gene products ofSaccharomyces cerevisiae


  • V. C. Vaidya
    • Department of Microbiology and Cell BiologyIndian Institute of Science
  • V. Seshadri
    • Department of Microbiology and Cell BiologyIndian Institute of Science
  • U. Vijayraghavan
    • Department of Microbiology and Cell BiologyIndian Institute of Science
Original Paper

DOI: 10.1007/BF02174384

Cite this article as:
Vaidya, V.C., Seshadri, V. & Vijayraghavan, U. Molec. Gen. Genet. (1996) 250: 267. doi:10.1007/BF02174384


The temperature-sensitiveprp24-1 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 temperaturesensitive (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 toprp21-1. This suppressor,prp21-2, accumulates pre-mRNA at the non-permissive temperature, a phenotype similar to that ofprp21-1. prp21-2 completely suppresses the splicing defect and restores in vivo levels of the U6 snRNA in theprp24-1 strain. Genetic analysis of the suppressor showed thatprp21-2 is not a bypass suppressor ofprp24-1. The suppression ofprp24-1 byprp21-2 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.

Key words

Pre-mRNA splicingSaccharomyces cerevisiaeSuppressorsprp24-1

Copyright information

© Springer-Verlag 1996