A novel RING-finger-like protein Ini1 is essential for cell cycle progression in fission yeast.
We have cloned a fission yeast (Schizosaccharomyces pombe) homologue of Ini, a novel RING-finger-like protein recently identified in rat that interacts with the connexin43 (cx43) promoter and might be important for the response of the cx43 gene to estrogen. S. pombe cells deleted for ini1(+) fail to form colonies and arrest with an elongated cell phenotype, indicating a cell cycle block. Cell cycle arrest is dependent on expression of Wee1, but not Rad3, suggesting that it occurs independently of the DNA damage checkpoint control. Analysis of mRNA intermediates in cells depleted for Ini1 demonstrates that Ini1 is required for pre-mRNA splicing. We observe an accumulation of pre-mRNA for six of seven genes analysed, suggesting that Ini1 is required for general splicing activity. Interestingly, loss of Ini1 results in cell death that is partially suppressed by elimination of the Wee1 kinase. Therefore, Wee1 might promote cell death in the absence of Ini1.
Oltra
Elisa
E
Department of Biochemistry and Molecular Biology, University of Miami School of Medicine, PO Box 016129, Miami, Florida 33101-1019, USA.
Verde
Fulvia
F
Werner
Rudolf
R
D'Urso
Gennaro
G
D000595:Amino Acid Sequence; D002453:Cell Cycle / Q000235:genetics*; D018797:Cell Cycle Proteins / Q000235:genetics / Q000378:metabolism; D002470:Cell Survival / Q000235:genetics; D064447:Checkpoint Kinase 2; D003001:Cloning, Molecular; D004249:DNA Damage; D004261:DNA Replication; D004268:DNA-Binding Proteins / Q000235:genetics* / Q000378:metabolism; D005800:Genes, Fungal; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D011494:Protein Kinases / Q000235:genetics / Q000378:metabolism; D011505:Protein-Tyrosine Kinases / Q000235:genetics / Q000378:metabolism; D012326:RNA Splicing / Q000235:genetics* / Q000502:physiology*; D012568:Schizosaccharomyces; D029702:Schizosaccharomyces pombe Proteins / Q000235:genetics* / Q000378:metabolism; D016415:Sequence Alignment; D017421:Sequence Analysis; D017386:Sequence Homology, Amino Acid
D018797:Cell Cycle Proteins; D004268:DNA-Binding Proteins; D009687:Nuclear Proteins; D029702:Schizosaccharomyces pombe Proteins; D011494:Protein Kinases; C068689:wee1 protein, S pombe; D064447:Checkpoint Kinase 2; D011505:Protein-Tyrosine Kinases; C456840:rad3 protein, S pombe