Identification and characterization of two novel components of the Prp19p-associated complex, Ntc30p and Ntc20p.
The yeast Saccharomyces cerevisiae Prp19p protein is an essential splicing factor and a spliceosomal component. It is not tightly associated with small nuclear RNAs (snRNAs) but is associated with a protein complex consisting of at least eight proteins. We have identified two novel components of the Prp19p-associated complex, Ntc30p and Ntc20p. Like other identified components of the complex, both Ntc30p and Ntc20p are associated with the spliceosome in the same manner as Prp19p immediately after or concurrently with dissociation of U4, indicating that the entire complex may bind to the spliceosome as an intact form. Neither Ntc30p nor Ntc20p directly interacts with Prp19p, but both interact with another component of the complex, Ntc85p. Immunoprecipitation analysis revealed an ordered interactions of these components in formation of the Prp19p-associated complex. Although null mutants of NTC30 or NTC20 showed no obvious growth phenotype, deletion of both genes impaired yeast growth resulting in accumulation of precursor mRNA. Extracts prepared from such a strain were defective in pre-mRNA splicing in vitro, but the splicing activity could be restored upon addition of the purified Prp19p-associated complex. These results indicate that Ntc30p and Ntc20p are auxiliary splicing factors the functions of which may be modulating the function of the Prp19p-associated complex.
Chen
C H
CH
Institute of Microbiology and Immunology, National Yang-Ming University, Shih-Pai 112, Taiwan, Republic of China.
Tsai
W Y
WY
Chen
H R
HR
Wang
C H
CH
Cheng
S C
SC
D000906:Antibodies; D002455:Cell Division; D003001:Cloning, Molecular; D005656:Fungal Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D005800:Genes, Fungal; D005804:Genes, Lethal; D046911:Macromolecular Substances; D008954:Models, Biological; D009154:Mutation / Q000235:genetics; D011233:Precipitin Tests; D011485:Protein Binding; D012326:RNA Splicing / Q000235:genetics; D000072260:RNA Splicing Factors; D012441:Saccharomyces cerevisiae / Q000737:chemistry / Q000235:genetics / Q000254:growth & development / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins; D017381:Spliceosomes / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D020798:Two-Hybrid System Techniques
D000906:Antibodies; D005656:Fungal Proteins; D046911:Macromolecular Substances; C079877:PRP19 protein, S cerevisiae; D000072260:RNA Splicing Factors; D029701:Saccharomyces cerevisiae Proteins