Control of spontaneous and damage-induced mutagenesis by SUMO and ubiquitin conjugation

Protein modification by ubiquitin is emerging as a signal for various biological processes in eukaryotes, including regulated proteolysis, but also for non-degradative functions such as protein localization, DNA repair and regulation of chromatin structure. A small ubiquitin-related modifier (SUMO) uses a similar conjugation system that sometimes counteracts the effects of ubiquitination. Ubiquitin and SUMO compete for modification of proliferating cell nuclear antigen (PCNA), an essential processivity factor for DNA replication and repair. Whereas multi-ubiquitination is mediated by components of the RAD6 pathway and promotes error-free repair, SUMO modification is associated with replication. Here we show that RAD6-mediated mono-ubiquitination of PCNA activates translesion DNA synthesis by the damage-tolerant polymerases η and ζ in yeast. Moreover, polymerase ζ is differentially affected by mono-ubiquitin and SUMO modification of PCNA. Whereas ubiquitination is required for damage-induced mutagenesis, both SUMO and mono-ubiquitin contribute to spontaneous mutagenesis in the absence of DNA damage. Our findings assign a function to SUMO during S phase and demonstrate how ubiquitin and SUMO, by regulating the accuracy of replication and repair, contribute to overall genomic stability.

[1]  S. Lauder,et al.  Yeast DNA Repair Proteins Rad6 and Rad18 Form a Heterodimer That Has Ubiquitin Conjugating, DNA Binding, and ATP Hydrolytic Activities* , 1997, The Journal of Biological Chemistry.

[2]  J P McDonald,et al.  Is Dna Damage Inducible and Functions in a Novel Error-free Postreplication Repair Mechanism , 1997 .

[3]  M. Hochstrasser,et al.  The Yeast ULP2 (SMT4) Gene Encodes a Novel Protease Specific for the Ubiquitin-Like Smt3 Protein , 2000, Molecular and Cellular Biology.

[4]  M. Hochstrasser,et al.  A new protease required for cell-cycle progression in yeast , 1999, Nature.

[5]  H. Ulrich.  Degradation or Maintenance: Actions of the Ubiquitin System on Eukaryotic Chromatin , 2002, Eukaryotic Cell.

[6]  C. Korch,et al.  Topical reversion at the HIS1 locus of Saccharomyces cerevisiae. A tale of three mutants. , 1998, Genetics.

[7]  R. Conaway,et al.  Emerging Roles of Ubiquitin in Transcription Regulation , 2002, Science.

[8]  P. Sung,et al.  Mutation of cysteine-88 in the Saccharomyces cerevisiae RAD6 protein abolishes its ubiquitin-conjugating activity and its various biological functions. , 1990, Proceedings of the National Academy of Sciences of the United States of America.

[9]  W. Xiao,et al.  MMS2, encoding a ubiquitin-conjugating-enzyme-like protein, is a member of the yeast error-free postreplication repair pathway. , 1998, Proceedings of the National Academy of Sciences of the United States of America.

[10]  Alexander Varshavsky,et al.  The yeast DNA repair gene RAD6 encodes a ubiquitin-conjugating enzyme , 1987, Nature.

[11]  C. Pickart,et al.  Noncanonical MMS2-Encoded Ubiquitin-Conjugating Enzyme Functions in Assembly of Novel Polyubiquitin Chains for DNA Repair , 1999, Cell.

[12]  C. Lawrence,et al.  UV mutagenesis in radiation-sensitive strains of yeast. , 1976, Genetics.

[13]  R. Borstel,et al.  The origin of spontaneous mutation in Saccharomyces cerevisiae. , 1980, Genetics.

[14]  F. Melchior,et al.  SUMO--nonclassical ubiquitin. , 2000, Annual review of cell and developmental biology.

[15]  L. Hicke.  Gettin' down with ubiquitin: turning off cell-surface receptors, transporters and channels. , 1999, Trends in cell biology.

[16]  F. Fabre,et al.  A similar defect in UV-induced mutagenesis conferred by the rad6 and rad18 mutations of Saccharomyces cerevisiae. , 1991, Mutation research.

[17]  R. Borstel,et al.  Spontaneous mutation by mutagenic repair of spontaneous lesions in DNA , 1976, Nature.

[18]  L. Prakash,et al.  Translesion DNA synthesis in eukaryotes: a one- or two-polymerase affair. , 2002, Genes & development.

[19]  L. Prakash,et al.  Interaction with PCNA is essential for yeast DNA polymerase eta function. , 2001, Molecular cell.

[20]  A. Haas,et al.  A ubiquitin mutant with specific defects in DNA repair and multiubiquitination , 1995, Molecular and cellular biology.

[21]  C. Lawrence.  The RAD6 DNA repair pathway in Saccharomyces cerevisiae: What does it do, and how does it do it? , 1994, BioEssays : news and reviews in molecular, cellular and developmental biology.

[22]  J. Lemontt,et al.  REV3, a Saccharomyces cerevisiae gene whose function is required for induced mutagenesis, is predicted to encode a nonessential DNA polymerase , 1989, Journal of bacteriology.

[23]  Boris Pfander,et al.  RAD6-dependent DNA repair is linked to modification of PCNA by ubiquitin and SUMO , 2002, Nature.

[24]  S. Jentsch,et al.  Two RING finger proteins mediate cooperation between ubiquitin‐conjugating enzymes in DNA repair , 2000, The EMBO journal.

[25]  C. Lawrence,et al.  Mutagenesis in eukaryotes dependent on DNA polymerase zeta and Rev1p. , 2001, Philosophical transactions of the Royal Society of London. Series B, Biological sciences.

[26]  Erica S. Johnson,et al.  An E3-like Factor that Promotes SUMO Conjugation to the Yeast Septins , 2001, Cell.

[27]  W. Xiao,et al.  UBC13, a DNA-damage-inducible gene, is a member of the error-free postreplication repair pathway in Saccharomyces cerevisiae , 2000, Current Genetics.