Project Summary/Abstract
DNA damage is a serious threat to genome stability. This is because it interferes with DNA
replication leading to mutations and chromosomal rearrangements – the hallmarks of cancer,
aging, and other diseases. To ensure genome stability, cells utilize DNA damage bypass
pathways to cope with DNA damage during replication. The long-term goal of our research
program is to understand how DNA damage bypass is carried out in eukaryotic systems at the
structural and mechanistic level. Our research will focus on two damage bypass pathways:
translesion synthesis and template switching. Progress in this field has slowed recently because
of the challenges associated with studying how the various bypass components assemble into
and function within large, dynamic, multi-protein complexes. We have developed the
biochemical, biological, biophysical, computational, and structural tools needed to overcome
these challenges. This puts us in a unique position to answer many fundamental questions
about damage bypass. Our future research plan is organized into three broad projects. First, we
will study the regulation of DNA damage bypass. This will be done by determining how bypass
complexes are assembled at stalled replication forks and by determining how this assembly is
controlled by PCNA-ubiquitylating enzymes. Second, we will study the mechanisms of
translesion synthesis. This will be done by determining how the most appropriate non-classical
polymerase is chosen to bypass the damage and by determining how each non-classical
polymerase accommodates damaged DNA templates. Third, we will study the mechanisms of
template switching. This will be done by determining how the remodeling of the replication fork
allows for the bypass of DNA damage and by determining how this process is carried out by
fork-remodeling DNA helicases. In answering these questions, we will gain important new
insights into the maintenance of genome stability.