Mutation in the prp12+ gene encoding a homolog of SAP130/SF3b130 causes differential inhibition of pre-mRNA splicing and arrest of cell-cycle progression in Schizosaccharomyces pombe.
prp12-1 is one of the mutants defective in pre-mRNA splicing at a nonpermissive temperature in Schizosaccharomyces pombe. We found that the prp12+ gene encodes a protein highly homologous with a human splicing factor, SAP130/SF3b130, a subunit of a U2 snRNP-associated complex SF3b. Prp12p was shown to interact genetically with Prp10p that is a homolog of SAP155/SF3b155, another subunit in SF3b, suggesting that Prp12p is a functional homolog of human SAP130/SF3b130. Prp12p tagged with GFP is uniformly localized in the nuclear DNA region. In addition to pre-mRNA splicing defects, the prp12-1 mutant produced elongated cells, a typical phenotype of cell division cycle (cdc) mutants, suggesting a possible link between pre-mRNA splicing and cell-cycle progression. We examined kinetics of splicing defects in prp12-1 and several other prp mutants using northern blot hybridization and found that, among all the tested pre-mRNAs, only Tflld pre-mRNA with low splicing efficiency showed detectable splicing defects at the nonpermissive temperature in prp12-1. In addition, we found that other prp mutants with the cdc phenotype also showed differential splicing defects in tested pre-mRNAs at the nonpermissive temperature. On the other hand, prp mutants that do not exhibit the cdc phenotype showed a rapid and complete block of pre-mRNA splicing in all the tested pre-mRNAs at the nonpermissive temperature, indicating that prp mutants with weak splicing defects have a tendency to exhibit the cdc phenotype. These results suggest that the cdc phenotype in prp12-1 is caused by a selective reduction of spliced transcripts encoding a protein (or proteins) required for G2/M transition.
Habara
Y
Y
Department of Biology, Graduate School of Sciences, Kyushu University, Fukuoka, Japan.
Urushiyama
S
S
Shibuya
T
T
Ohshima
Y
Y
Tani
T
T
D000595:Amino Acid Sequence; D000818:Animals; D002453:Cell Cycle; D002467:Cell Nucleus / Q000378:metabolism; D003001:Cloning, Molecular; D005656:Fungal Proteins / Q000235:genetics* / Q000378:metabolism / Q000502:physiology; D005800:Genes, Fungal / Q000502:physiology*; D049452:Green Fluorescent Proteins; D006801:Humans; D007438:Introns; D007700:Kinetics; D008164:Luminescent Proteins / Q000378:metabolism; D008969:Molecular Sequence Data; D016296:Mutagenesis; D010750:Phosphoproteins; D012322:RNA Precursors; D012326:RNA Splicing; D000072260:RNA Splicing Factors; D012331:RNA, Fungal; D016601:RNA-Binding Proteins; D017413:Ribonucleoprotein, U2 Small Nuclear; D012568:Schizosaccharomyces / Q000166:cytology / Q000235:genetics; D029702:Schizosaccharomyces pombe Proteins; D013696:Temperature; D035362:Transcription Factor TFIID; D019473:Transcription Factors, TFII / Q000378:metabolism
D005656:Fungal Proteins; D008164:Luminescent Proteins; D010750:Phosphoproteins; C428363:Prp12 protein, S pombe; D012322:RNA Precursors; D000072260:RNA Splicing Factors; D012331:RNA, Fungal; D016601:RNA-Binding Proteins; D017413:Ribonucleoprotein, U2 Small Nuclear; C112491:SF3B1 protein, human; C486349:SF3B3 protein, human; D029702:Schizosaccharomyces pombe Proteins; C491799:Sf3b1 protein, mouse; D035362:Transcription Factor TFIID; D019473:Transcription Factors, TFII; D049452:Green Fluorescent Proteins