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ago1 and dcr1, two core components of the RNA interference pathway, functionally diverge from rdp1 in regulating cell cycle events in Schizosaccharomyces pombe.
- Source :
- Molecular Biology of the Cell; March 2004, Vol. 15 Issue: 3 p1425-35, 11p
- Publication Year :
- 2004
-
Abstract
- In the fission yeast Schizosaccharomyces pombe, three genes that function in the RNA interference (RNAi) pathway, ago1+, dcr1+, and rdp1+, have recently been shown to be important for timely formation of heterochromatin and accurate chromosome segregation. In the present study, we present evidence that null mutants for ago1+ and dcr1+ but not rdp1+, exhibit abnormal cytokinesis, cell cycle arrest deficiencies, and mating defects. Subsequent analyses showed that ago1+ and dcr1+ are required for regulated hyperphosphorylation of Cdc2 when encountering genotoxic insults. Because rdp1+ is dispensable for this process, the functions of ago1+ and dcr1+ in this pathway are presumably independent of their roles in RNAi-mediated heterochromatin formation and chromosome segregation. This was further supported by the finding that ago1+ is a multicopy suppressor of the S-M checkpoint deficiency and cytokinesis defects associated with loss of Dcr1 function, but not for the chromosome segregation defects of this mutant. Accordingly, we conclude that Dcr1-dependent production of small interfering RNAs is not required for enactment and/or maintenance of certain cell cycle checkpoints and that Ago1 and Dcr1 functionally diverge from Rdp1 to control cell cycle events in fission yeast. Finally, exogenous expression of hGERp95/EIF2C2/hAgo2, a human Ago1 homolog implicated in posttranscriptional gene silencing, compensated for the loss of ago1+ function in S. pombe. This suggests that PPD proteins may also be important for regulation of cell cycle events in higher eukaryotes.
Details
- Language :
- English
- ISSN :
- 10591524 and 19394586
- Volume :
- 15
- Issue :
- 3
- Database :
- Supplemental Index
- Journal :
- Molecular Biology of the Cell
- Publication Type :
- Periodical
- Accession number :
- ejs7035497