Bi-directional routing of DNA mismatch repair protein human exonuclease 1 to replication foci and DNA double strand breaks.
Human exonuclease 1 (hEXO1) is implicated in DNA metabolism, including replication, recombination and repair, substantiated by its interactions with PCNA, DNA helicases BLM and WRN, and several DNA mismatch repair (MMR) proteins. We investigated the sub-nuclear localization of hEXO1 during S-phase progression and in response to laser-induced DNA double strand breaks (DSBs). We show that hEXO1 and PCNA co-localize in replication foci. This apparent interaction is sustained throughout S-phase. We also demonstrate that hEXO1 is rapidly recruited to DNA DSBs. We have identified a PCNA interacting protein (PIP-box) region on hEXO1 located in its COOH-terminal ((788)QIKLNELW(795)). This motif is essential for PCNA binding and co-localization during S-phase. Recruitment of hEXO1 to DNA DSB sites is dependent on the MMR protein hMLH1. We show that two distinct hMLH1 interaction regions of hEXO1 (residues 390-490 and 787-846) are required to direct the protein to the DNA damage site. Our results reveal that protein domains in hEXO1 in conjunction with specific protein interactions control bi-directional routing of hEXO1 between on-going DNA replication and repair processes in living cells.
Center for Healthy Aging, Department of Cellular and Molecular Medicine, University of Copenhagen, Copenhagen, Denmark.
Sascha E
SE
Liberti
Sofie D
SD
Andersen
Jing
J
Wang
Alfred
A
May
Simona
S
Miron
Mylene
M
Perderiset
Guido
G
Keijzers
Finn C
FC
Nielsen
Jean-Baptiste
JB
Charbonnier
Vilhelm A
VA
Bohr
Lene J
LJ
Rasmussen
D048868:Adaptor Proteins, Signal Transducing / Q000235:genetics / Q000378:metabolism; D020816:Amino Acid Motifs; D019943:Amino Acid Substitution; D000818:Animals; D004247:DNA / Q000235:genetics / Q000378:metabolism; D053903:DNA Breaks, Double-Stranded / Q000528:radiation effects*; D053843:DNA Mismatch Repair / Q000502:physiology* / Q000528:radiation effects; D045643:DNA Repair Enzymes / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects; D004261:DNA Replication / Q000502:physiology* / Q000528:radiation effects; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005090:Exodeoxyribonucleases / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects; D006367:HeLa Cells; D006801:Humans; D007834:Lasers / Q000009:adverse effects; D051379:Mice; D000070957:MutL Protein Homolog 1; D000074081:MutS Homolog 3 Protein; D041681:NIH 3T3 Cells; D009687:Nuclear Proteins / Q000235:genetics / Q000378:metabolism; D018809:Proliferating Cell Nuclear Antigen / Q000235:genetics / Q000378:metabolism; D021381:Protein Transport / Q000235:genetics / Q000528:radiation effects; D053484:RecQ Helicases / Q000235:genetics / Q000378:metabolism; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism* / Q000528:radiation effects; D016196:S Phase; D000071657:Werner Syndrome Helicase
D048868:Adaptor Proteins, Signal Transducing; D004268:DNA-Binding Proteins; C501486:MLH1 protein, human; C078444:MSH3 protein, human; D000074081:MutS Homolog 3 Protein; D009687:Nuclear Proteins; D018809:Proliferating Cell Nuclear Antigen; D011993:Recombinant Fusion Proteins; D004247:DNA; C114331:EXO1 protein, human; D005090:Exodeoxyribonucleases; C097151:Bloom syndrome protein; D000070957:MutL Protein Homolog 1; D053484:RecQ Helicases; C098785:WRN protein, human; D000071657:Werner Syndrome Helicase; D045643:DNA Repair Enzymes