Originally published as Genetics Published Articles Ahead of Print on August 30, 2008.

Genetics, Vol. 180, 73-82, September 2008, Copyright © 2008
doi:10.1534/genetics.108.091066

Requirement of Rad5 for DNA Polymerase {zeta}-Dependent Translesion Synthesis in Saccharomyces cerevisiae

Vincent Pagès*, Anne Bresson{dagger}, Narottam Acharya*, Satya Prakash*, Robert P. Fuchs{ddagger} and Louise Prakash*,1

* Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, Galveston, Texas 77555-1061, {dagger} Department Intégrité du Génome, UMR7175 Centre National de la Recherche Scientifique/Université Louis Pasteur, Ecole Supérieure de Biotechnologie de Strasbourg, Bld S. Brant, BP 10413, 67412 Illkirch, France and {ddagger} CNRS, Unité Propre de Recherche 3081, Genome Instability and Carcinogenesis Conventionné par l'Université d'Aix-Marseille 2, 13402 Marseille Cedex 20, France

1 Corresponding author: Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, 301 University Blvd., Galveston, TX 77555-1061.
E-mail: l.prakash{at}utmb.edu

In yeast, Rad6–Rad18-dependent lesion bypass involves translesion synthesis (TLS) by DNA polymerases {eta} or {zeta} or Rad5-dependent postreplication repair (PRR) in which error-free replication through the DNA lesion occurs by template switching. Rad5 functions in PRR via its two distinct activities—a ubiquitin ligase that promotes Mms2–Ubc13-mediated K63-linked polyubiquitination of PCNA at its lysine 164 residue and a DNA helicase that is specialized for replication fork regression. Both these activities are important for Rad5's ability to function in PRR. Here we provide evidence for the requirement of Rad5 in TLS mediated by Pol{zeta}. Using duplex plasmids carrying different site-specific DNA lesions—an abasic site, a cis–syn TT dimer, a (6-4) TT photoproduct, or a G-AAF adduct—we show that Rad5 is needed for Pol{zeta}-dependent TLS. Rad5 action in this role is likely to be structural, since neither the inactivation of its ubiquitin ligase activity nor the inactivation of its helicase activity impairs its role in TLS.