DNA polymerases ζ and Rev1 mediate error-prone bypass of non-B DNA structures.
DNA polymerase ζ (Pol ζ) and Rev1 are key players in translesion DNA synthesis. The error-prone Pol ζ can also participate in replication of undamaged DNA when the normal replisome is impaired. Here we define the nature of the replication disturbances that trigger the recruitment of error-prone polymerases in the absence of DNA damage and describe the specific roles of Rev1 and Pol ζ in handling these disturbances. We show that Pol ζ/Rev1-dependent mutations occur at sites of replication stalling at short repeated sequences capable of forming hairpin structures. The Rev1 deoxycytidyl transferase can take over the stalled replicative polymerase and incorporate an additional 'C' at the hairpin base. Full hairpin bypass often involves template-switching DNA synthesis, subsequent realignment generating multiply mismatched primer termini and extension of these termini by Pol ζ. The postreplicative pathway dependent on polyubiquitylation of proliferating cell nuclear antigen provides a backup mechanism for accurate bypass of these sequences that is primarily used when the Pol ζ/Rev1-dependent pathway is inactive. The results emphasize the pivotal role of noncanonical DNA structures in mutagenesis and reveal the long-sought-after mechanism of complex mutations that represent a unique signature of Pol ζ.
Eppley Institute for Research in Cancer and Allied Diseases, University of Nebraska Medical Center, Omaha, NE 68118, USA and Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, MO 63110, USA.
Matthew R
MR
Northam
Elizabeth A
EA
Moore
Tony M
TM
Mertz
Sara K
SK
Binz
Carrie M
CM
Stith
Elena I
EI
Stepchenkova
Kathern L
KL
Wendt
Peter M J
PM
Burgers
Polina V
PV
Shcherbakova
D004247:DNA / Q000096:biosynthesis* / Q000737:chemistry*; D004261:DNA Replication; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D016296:Mutagenesis; D009154:Mutation; D009690:Nucleic Acid Conformation; D009713:Nucleotidyltransferases / Q000737:chemistry / Q000378:metabolism*; D012091:Repetitive Sequences, Nucleic Acid; D012441:Saccharomyces cerevisiae / Q000235:genetics; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry / Q000378:metabolism*; D000099270:Y-Family DNA Polymerases
D004247:DNA; D004259:DNA-Directed DNA Polymerase; D009713:Nucleotidyltransferases; D029701:Saccharomyces cerevisiae Proteins; C100951:REV1 protein, S cerevisiae; D000099270:Y-Family DNA Polymerases; C092602:REV3 protein, S cerevisiae