THE PRP31 GENE ENCODES A NOVEL PROTEIN REQUIRED FOR PRE-MESSENGER-RNASPLICING IN SACCHAROMYCES-CEREVISIAE

The pre-mRNA splicing factor Prp31p was identified in a screen of temp erature-sensitive yeast strains for those exhibiting a splicing defect upon shift to the non-permissive temperature, The wild-type PRP31 gen e was cloned and shown to be essential for cell viability, The PRP31 g ene is predicted to encode a 60 kDa polypeptide, No similarities with other known splicing factors or motifs indicative of protein-protein o r RNA-protein interaction domains are discernible in the predicted ami no acid sequence. A PRP31 allele bearing a triple repeat of the hemagg lutinin epitope has been generated. The tagged protein is functional i n vivo and a single polypeptide species of the predicted size was dete cted by Western analysis with proteins from yeast cell extracts. Funct ional Prp31p is required for the processing of pre-mRNA species both i n vivo and in vitro, indicating that the protein is directly involved in the splicing pathway.