MECHANISTIC STUDIES OF REPLICATION FORK REMODELING BY DNA TRANSLOCASES
Warren, Garrett M
:
2019-05-15
Abstract
During DNA replication the replication fork can become stalled by impediments that prevent complete and accurate duplication of the genome. DNA replication fork
reversal is an important pathway for the protection and restoration of stalled DNA
replication forks in both prokaryotes and eukaryotes to preserve genome stability.
Several enzymes known as fork remodelers initiate this pathway by actively reversing a
stalled DNA replication fork, although their mechanisms of action are not well
understood. This dissertation presents work characterizing fork reversal mechanisms of
the prokaryotic fork remodeler RecG and the eukaryotic SNF2-family fork remodelers
SMARCAL1, ZRANB3, and HLTF. Biophysical analysis of RecG binding to a model
DNA replication fork revealed how conformational changes within the motor domain
upon binding DNA is required for efficient fork reversal activity. Comparison of fork
reversal mechanisms of the eukaryotic fork remodelers show differences in sensitivity to
DNA damage on the leading and lagging strand template, providing a rationale for the
multiple non-redundant fork remodeling activities in the cell. This work has expanded
our knowledge of how these enzymes recognize and remodel stalled replication forks to
ensure genome stability.