Abstract
We describe two RING finger proteins in the fission yeast Schizosaccharomyces pombe, Rfp1 and Rfp2. We show that these proteins function redundantly in DNA repair. Rfp1 was isolated as a Chk1-interacting protein in a two-hybrid screen and has high amino acid sequence similarity to Rfp2. Deletion of either gene does not cause a phenotype, but a double deletion (rfp1Deltarfp2Delta) showed poor viability and defects in cell cycle progression. These cells are also sensitive to DNA-damaging agents, although they maintained normal checkpoint signaling to Chk1. Rfp1 and Rfp2 are most closely related to human Rnf4, and we showed that Rnf4 can substitute functionally for Rfp1 and/or Rfp2. The double mutants also showed significantly increased levels of protein SUMOylation, and we identified an S. pombe Ulp2/Smt4 homolog that, when overexpressed, reduced SUMO levels and suppressed the DNA damage sensitivity of rfp1Delta rfp2Delta cells.
Publication types
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Research Support, N.I.H., Extramural
MeSH terms
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Cell Cycle / physiology*
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Checkpoint Kinase 1
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DNA Repair / physiology*
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DNA, Fungal / genetics
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DNA, Fungal / metabolism*
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Gene Deletion
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Humans
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Nuclear Proteins / genetics
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Nuclear Proteins / metabolism
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Protein Kinases / genetics
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Protein Kinases / metabolism
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Protein Processing, Post-Translational
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Schizosaccharomyces / genetics
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Schizosaccharomyces / metabolism*
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Schizosaccharomyces pombe Proteins / genetics
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Schizosaccharomyces pombe Proteins / metabolism*
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Sequence Homology, Amino Acid
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Small Ubiquitin-Related Modifier Proteins / genetics
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Small Ubiquitin-Related Modifier Proteins / metabolism
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Transcription Factors / genetics
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Transcription Factors / metabolism*
Substances
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DNA, Fungal
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Nuclear Proteins
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RNF4 protein, human
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Rfp1 protein, S pombe
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Rfp2 protein, S pombe
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Schizosaccharomyces pombe Proteins
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Small Ubiquitin-Related Modifier Proteins
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Transcription Factors
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Protein Kinases
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CHEK1 protein, human
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Checkpoint Kinase 1
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Chk1 protein, S pombe