TY - JOUR
T1 - Human RECQ1 and RECQ4 helicases play distinct roles in DNA replication initiation
AU - Thangavel, Saravanabhavan
AU - Mendoza-Maldonado, Ramiro
AU - Tissino, Erika
AU - Sidorova, Julia M.
AU - Yin, Jinhu
AU - Wang, Weidong
AU - Monnat, Raymond J.
AU - Falaschi, Arturo
AU - Vindigni, Alessandro
PY - 2010/3
Y1 - 2010/3
N2 - Cellular and biochemical studies support a role for all five human RecQ helicases in DNA replication; however, their specific functions during this process are unclear. Here we investigate the in vivo association of the five human RecQ helicases with three well-characterized human replication origins. We show that only RECQ1 (also called RECQL or RECQL1) and RECQ4 (also called RECQL4) associate with replication origins in a cell cycle-regulated fashion in unperturbed cells. RECQ4 is recruited to origins at late G1, after ORC and MCM complex assembly, while RECQ1 and additional RECQ4 are loaded at origins at the onset of S phase, when licensed origins begin firing. Both proteins are lost from origins after DNA replication initiation, indicating either disassembly or tracking with the newly formed replisome. Nascent-origin DNA synthesis and the frequency of origin firing are reduced after RECQ1 depletion and, to a greater extent, after RECQ4 depletion. Depletion of RECQ1, though not that of RECQ4, also suppresses replication fork rates in otherwise unperturbed cells. These results indicate that RECQ1 and RECQ4 are integral components of the human replication complex and play distinct roles in DNA replication initiation and replication fork progression in vivo.
AB - Cellular and biochemical studies support a role for all five human RecQ helicases in DNA replication; however, their specific functions during this process are unclear. Here we investigate the in vivo association of the five human RecQ helicases with three well-characterized human replication origins. We show that only RECQ1 (also called RECQL or RECQL1) and RECQ4 (also called RECQL4) associate with replication origins in a cell cycle-regulated fashion in unperturbed cells. RECQ4 is recruited to origins at late G1, after ORC and MCM complex assembly, while RECQ1 and additional RECQ4 are loaded at origins at the onset of S phase, when licensed origins begin firing. Both proteins are lost from origins after DNA replication initiation, indicating either disassembly or tracking with the newly formed replisome. Nascent-origin DNA synthesis and the frequency of origin firing are reduced after RECQ1 depletion and, to a greater extent, after RECQ4 depletion. Depletion of RECQ1, though not that of RECQ4, also suppresses replication fork rates in otherwise unperturbed cells. These results indicate that RECQ1 and RECQ4 are integral components of the human replication complex and play distinct roles in DNA replication initiation and replication fork progression in vivo.
UR - http://www.scopus.com/inward/record.url?scp=77749330814&partnerID=8YFLogxK
U2 - 10.1128/MCB.01290-09
DO - 10.1128/MCB.01290-09
M3 - Article
C2 - 20065033
AN - SCOPUS:77749330814
SN - 0270-7306
VL - 30
SP - 1382
EP - 1396
JO - Molecular and cellular biology
JF - Molecular and cellular biology
IS - 6
ER -