Cloning of the two essential yeast genes, PRP6 and PRP9, and their rapid mapping, disruption and partial sequencing...

In the yeast Saccharomyces cerevisiae, some thermosensitive (ts) mutants have been shown to be impaired in pre-mRNA splicing (prp mutants). From a yeast genomic library, we have isolated plasmids that complement prp6 or prp9 ts mutations. These plasmids also complement the ts growth defect of additional independent mutants identified as new prp6 and prp9 ts alleles, indicating that the cloned DNAs encode PRP6 and PRP9 genes, respectively. Here, we describe the restriction maps of these loci which are localized on chromosome II and IV, respectively. The limits of open reading frames (ORFs) within the cloned inserts have been determined using a linker insertion strategy combined with the ts complementation assay. Double-strand DNA sequencing was also performed directly on the yeast expression vector from the inserted linkers. Gene disruption experiments demonstrate that both genes are essential for viability.