title: Snt309p, a component of the Prp19p-associated complex that interacts with Prp19p and associates with the spliceosome simultaneously with or immediately after dissociation of U4 in the same manner as Prp19p.
abstract: The yeast protein Prp19p is essential for pre-mRNA splicing and is associated with the spliceosome concurrently with or just after dissociation of U4 small nuclear RNA. In splicing extracts, Prp19p is associated with several other proteins in a large protein complex of unknown function, but at least one of these proteins is also essential for splicing (W.-Y. Tarn, C.-H. Hsu, K.-T. Huang, H.-R. Chen, H.-Y. Kao, K.-R. Lee, and S.-C. Cheng, EMBO J. 13:2421-2431, 1994). To identify proteins in the Prp19p-associated complex, we have isolated trans-acting mutations that exacerbate the phenotypes of conditional alleles of prp19, using the ade2-ade3 sectoring system. A novel splicing factor, Snt309p, was identified through such a screen. Although the SNT309 gene was not essential for growth of Saccharomyces cerevisiae under normal conditions, yeast cells containing a null allele of the SNT309 gene were temperature sensitive and accumulated pre-mRNA at the nonpermissive temperature. Far-Western blot analysis revealed direct interaction between Prp19p and Snt309p. Snt309p was shown to be a component of the Prp19p-associated complex by Western blot analysis. Immunoprecipitation studies demonstrated that Snt309p was also a spliceosomal component and associated with the spliceosome in the same manner as Prp19p during spliceosome assembly. These results suggest that the functions of Prp19p and Snt309p in splicing may require coordinate action of these two proteins.
authors.affiliation: Institute of Microbiology and Immunology, National Yang-Ming University, Shih-Pai, Taiwan, Republic of China.
authors.forename: H R
authors.initials: HR
authors.lastname: Chen
authors.forename: S P
authors.initials: SP
authors.lastname: Jan
authors.forename: T Y
authors.initials: TY
authors.lastname: Tsao
authors.forename: Y J
authors.initials: YJ
authors.lastname: Sheu
authors.forename: J
authors.initials: J
authors.lastname: Banroques
authors.forename: S C
authors.initials: SC
authors.lastname: Cheng
mesh_terms: D000595:Amino Acid Sequence; D001483:Base Sequence; D003001:Cloning, Molecular; D004271:DNA, Fungal; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D005804:Genes, Lethal; D005813:Genes, Synthetic; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010641:Phenotype; D011485:Protein Binding; D012326:RNA Splicing; D000072260:RNA Splicing Factors; D012333:RNA, Messenger / Q000378:metabolism; D017414:Ribonucleoprotein, U4-U6 Small Nuclear / Q000378:metabolism*; D012441:Saccharomyces cerevisiae; D029701:Saccharomyces cerevisiae Proteins; D017381:Spliceosomes / Q000378:metabolism*; D013696:Temperature
chemical_list: D004271:DNA, Fungal; D005656:Fungal Proteins; C079877:PRP19 protein, S cerevisiae; D000072260:RNA Splicing Factors; D012333:RNA, Messenger; D017414:Ribonucleoprotein, U4-U6 Small Nuclear; C112008:SNT309 protein, S cerevisiae; D029701:Saccharomyces cerevisiae Proteins