The processing of Holliday junctions by BLM and WRN helicases is regulated by p53.
BLM, WRN, and p53 are involved in the homologous DNA recombination pathway. The DNA structure-specific helicases, BLM and WRN, unwind Holliday junctions (HJ), an activity that could suppress inappropriate homologous recombination during DNA replication. Here, we show that purified, recombinant p53 binds to BLM and WRN helicases and attenuates their ability to unwind synthetic HJ in vitro. The p53 248W mutant reduces abilities of both to bind HJ and inhibit helicase activities, whereas the p53 273H mutant loses these abilities. Moreover, full-length p53 and a C-terminal polypeptide (residues 373-383) inhibit the BLM and WRN helicase activities, but phosphorylation at Ser(376) or Ser(378) completely abolishes this inhibition. Following blockage of DNA replication, Ser(15) phospho-p53, BLM, and RAD51 colocalize in nuclear foci at sites likely to contain DNA replication intermediates in cells. Our results are consistent with a novel mechanism for p53-mediated regulation of DNA recombinational repair that involves p53 post-translational modifications and functional protein-protein interactions with BLM and WRN DNA helicases.
Yang
Qin
Q
Laboratory of Human Carcinogenesis, National Cancer Institute, National Institutes of Health, Bethesda, Maryland 20892, USA.
Zhang
Ran
R
Wang
Xin Wei
XW
Spillare
Elisa A
EA
Linke
Steven P
SP
Subramanian
Deepa
D
Griffith
Jack D
JD
Li
Ji Liang
JL
Hickson
Ian D
ID
Shen
Jiang Cheng
JC
Loeb
Lawrence A
LA
Mazur
Sharlyn J
SJ
Appella
Ettore
E
Brosh
Robert M
RM
Karmakar
Parimal
P
Bohr
Vilhelm A
VA
Harris
Curtis C
CC
D000251:Adenosine Triphosphatases / Q000378:metabolism*; D001665:Binding Sites; D002460:Cell Line; D004265:DNA Helicases / Q000378:metabolism*; D005090:Exodeoxyribonucleases; D019084:Fluorescent Antibody Technique, Indirect; D006801:Humans; D007700:Kinetics; D008214:Lymphocytes; D016296:Mutagenesis; D053484:RecQ Helicases; D011993:Recombinant Fusion Proteins / Q000378:metabolism; D016159:Tumor Suppressor Protein p53 / Q000378:metabolism; D000071657:Werner Syndrome Helicase
D011993:Recombinant Fusion Proteins; D016159:Tumor Suppressor Protein p53; D005090:Exodeoxyribonucleases; D000251:Adenosine Triphosphatases; C097151:Bloom syndrome protein; D004265:DNA Helicases; D053484:RecQ Helicases; C098785:WRN protein, human; D000071657:Werner Syndrome Helicase