Proliferating cell nuclear antigen promotes translesion synthesis by DNA polymerase zeta.
DNA polymerase zeta (Pol zeta), a heterodimer of Rev3 and Rev7, is essential for DNA damage provoked mutagenesis in eukaryotes. DNA polymerases that function in a processive complex with the replication clamp proliferating cell nuclear antigen (PCNA) have been shown to possess a close match to the consensus PCNA-binding motif QxxLxxFF. This consensus motif is lacking in either subunit of Pol zeta, yet its activity is stimulated by PCNA. In particular, translesion synthesis of UV damage-containing DNA is dramatically stimulated by PCNA such that translesion synthesis rates are comparable with replication rates by Pol zeta on undamaged DNA. PCNA also stimulated translesion synthesis of a model abasic site by Pol zeta. Efficient PCNA stimulation required that PCNA was prevented from sliding off the damage-containing model oligonucleotide template-primer through the use of biotin-streptavidin bumpers or other blocks. Under those experimental conditions, facile bypass of the abasic site was also detected by DNA polymerase delta or eta (Rad30). The yeast DNA damage checkpoint clamp, consisting of Rad17, Mec3, and Ddc1, and an ortholog of human 9-1-1, has been implicated in damage-induced mutagenesis. However, this checkpoint clamp did not stimulate translesion synthesis by Pol zeta or by DNA polymerase delta.
Garg
Parie
P
Department of Biochemistry and Molecular Biophysics, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Stith
Carrie M
CM
Majka
Jerzy
J
Burgers
Peter M J
PM
D001483:Base Sequence; D004249:DNA Damage; D017931:DNA Primers; D004260:DNA Repair / Q000502:physiology*; D004259:DNA-Directed DNA Polymerase / Q000302:isolation & purification / Q000378:metabolism; D018809:Proliferating Cell Nuclear Antigen / Q000502:physiology*; D014466:Ultraviolet Rays
D017931:DNA Primers; D018809:Proliferating Cell Nuclear Antigen; C425929:DNA polymerase zeta; D004259:DNA-Directed DNA Polymerase