title: PRP38 encodes a yeast protein required for pre-mRNA splicing and maintenance of stable U6 small nuclear RNA levels.
abstract: An essential pre-mRNA splicing factor, the product of the PRP38 gene, has been genetically identified in a screen of temperature-sensitive mutants of Saccharomyces cerevisiae. Shifting temperature-sensitive prp38 cultures from 23 to 37 degrees C prevents the first cleavage-ligation event in the excision of introns from mRNA precursors. In vitro splicing inactivation and complementation studies suggest that the PRP38-encoded factor functions, at least in part, after stable splicing complex formation. The PRP38 locus contains a 726-bp open reading frame coding for an acidic 28-kDa polypeptide (PRP38). While PRP38 lacks obvious structural similarity to previously defined splicing factors, heat inactivation of PRP38, PRP19, or any of the known U6 (or U4/U6) small nuclear ribonucleoprotein-associating proteins (i.e., PRP3, PRP4, PRP6, and PRP24) leads to a common, unexpected consequence: intracellular U6 small nuclear RNA (snRNA) levels decrease as splicing activity is lost. Curiously, U4 snRNA, normally extensively base paired with U6 snRNA, persists in the virtual absence of U6 snRNA.
authors.affiliation: T.H. Morgan School of Biological Sciences, University of Kentucky, Lexington 40506-0225.
authors.forename: S
authors.initials: S
authors.lastname: Blanton
authors.forename: A
authors.initials: A
authors.lastname: Srinivasan
authors.forename: B C
authors.initials: BC
authors.lastname: Rymond
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D004271:DNA, Fungal; D005656:Fungal Proteins / Q000235:genetics*; D005804:Genes, Lethal; D006358:Hot Temperature; D007700:Kinetics; D008969:Molecular Sequence Data; D009154:Mutation; D012322:RNA Precursors / Q000378:metabolism*; D012326:RNA Splicing / Q000235:genetics*; D000072260:RNA Splicing Factors; D012331:RNA, Fungal / Q000378:metabolism; D012342:RNA, Small Nuclear / Q000378:metabolism*; D015183:Restriction Mapping; D012441:Saccharomyces cerevisiae / Q000235:genetics*; D029701:Saccharomyces cerevisiae Proteins
chemical_list: D004271:DNA, Fungal; D005656:Fungal Proteins; C076234:PRP38 protein, S cerevisiae; D012322:RNA Precursors; D000072260:RNA Splicing Factors; D012331:RNA, Fungal; D012342:RNA, Small Nuclear; D029701:Saccharomyces cerevisiae Proteins