TY - JOUR
T1 - Chk1 requirement for high global rates of replication fork progression during normal vertebrate S phase
AU - Petermann, Eva
AU - Maya-Mendoza, Apolinar
AU - Zachos, George
AU - Gillespie, David A F
AU - Jackson, Dean A
AU - Caldecott, Keith W
PY - 2006
Y1 - 2006
N2 - Chk1 protein kinase maintains replication fork stability in metazoan cells in response to DNA damage and DNA replication inhibitors. Here, we have employed DNA fiber labeling to quantify, for the first time, the extent to which Chk1 maintains global replication fork rates during normal vertebrate S phase. We report that replication fork rates in Chk1(-/-) chicken DT40 cells are on average half of those observed with wild-type cells. Similar results were observed if Chk1 was inhibited or depleted in wild-type DT40 cells or HeLa cells by incubation with Chk1 inhibitor or small interfering RNA. In addition, reduced rates of fork extension were observed with permeabilized Chk1(-/-) cells in vitro. The requirement for Chk1 for high fork rates during normal S phase was not to suppress promiscuous homologous recombination at replication forks, because inhibition of Chk1 similarly slowed fork progression in XRCC3(-/-) DT40 cells. Rather, we observed an increased number of replication fibers in Chk1(-/-) cells in which the nascent strand is single-stranded, supporting the idea that slow global fork rates in unperturbed Chk1(-/-) cells are associated with the accumulation of aberrant replication fork structures.
AB - Chk1 protein kinase maintains replication fork stability in metazoan cells in response to DNA damage and DNA replication inhibitors. Here, we have employed DNA fiber labeling to quantify, for the first time, the extent to which Chk1 maintains global replication fork rates during normal vertebrate S phase. We report that replication fork rates in Chk1(-/-) chicken DT40 cells are on average half of those observed with wild-type cells. Similar results were observed if Chk1 was inhibited or depleted in wild-type DT40 cells or HeLa cells by incubation with Chk1 inhibitor or small interfering RNA. In addition, reduced rates of fork extension were observed with permeabilized Chk1(-/-) cells in vitro. The requirement for Chk1 for high fork rates during normal S phase was not to suppress promiscuous homologous recombination at replication forks, because inhibition of Chk1 similarly slowed fork progression in XRCC3(-/-) DT40 cells. Rather, we observed an increased number of replication fibers in Chk1(-/-) cells in which the nascent strand is single-stranded, supporting the idea that slow global fork rates in unperturbed Chk1(-/-) cells are associated with the accumulation of aberrant replication fork structures.
U2 - 10.1128/MCB.26.8.3319-3326.2006
DO - 10.1128/MCB.26.8.3319-3326.2006
M3 - Article
C2 - 16581803
SN - 0270-7306
VL - 26
SP - 3319
EP - 3326
JO - Molecular and Cellular Biology
JF - Molecular and Cellular Biology
IS - 8
ER -