A forward chemical genetic screen reveals an inhibitor of the Mre11-Rad50-Nbs1 complex.
The MRN (Mre11-Rad50-Nbs1)-ATM (ataxia-telangiectasia mutated) pathway is essential for sensing and signaling from DNA double-strand breaks. The MRN complex acts as a DNA damage sensor, maintains genome stability during DNA replication, promotes homology-dependent DNA repair and activates ATM. MRN is essential for cell viability, which has limited functional studies of the complex. Small-molecule inhibitors of MRN could circumvent this experimental limitation and could also be used as cellular radio- and chemosensitization compounds. Using cell-free systems that recapitulate faithfully the MRN-ATM signaling pathway, we designed a forward chemical genetic screen to identify inhibitors of the pathway, and we isolated 6-(4-hydroxyphenyl)-2-thioxo-2,3-dihydro-4(1H)-pyrimidinone (mirin, 1) as an inhibitor of MRN. Mirin prevents MRN-dependent activation of ATM without affecting ATM protein kinase activity, and it inhibits Mre11-associated exonuclease activity. Consistent with its ability to target the MRN complex, mirin abolishes the G2/M checkpoint and homology-dependent repair in mammalian cells.
Dupré
Aude
A
Columbia University, Institute for Cancer Genetics, Irving Cancer Research Center, 1130 St. Nicholas Avenue, Room 602, New York, New York 10032, USA.
Boyer-Chatenet
Louise
L
Sattler
Rose M
RM
Modi
Ami P
AP
Lee
Ji-Hoon
JH
Nicolette
Matthew L
ML
Kopelovich
Levy
L
Jasin
Maria
M
Baer
Richard
R
Paull
Tanya T
TT
Gautier
Jean
J
D018528:ATP-Binding Cassette Transporters / Q000378:metabolism*; D000818:Animals; D001260:Ataxia Telangiectasia / Q000235:genetics / Q000378:metabolism; D002453:Cell Cycle / Q000187:drug effects; D002457:Cell Extracts; D002460:Cell Line; D004268:DNA-Binding Proteins / Q000378:metabolism*; D015195:Drug Design; D006801:Humans; D000076228:MRE11 Homologue Protein; D015394:Molecular Structure; D011485:Protein Binding; D011744:Pyrimidinones / Q000737:chemistry / Q000494:pharmacology*; D015398:Signal Transduction / Q000187:drug effects; D013871:Thiones / Q000737:chemistry / Q000494:pharmacology*; D025521:Tumor Suppressor Proteins / Q000378:metabolism*; D029867:Xenopus Proteins / Q000378:metabolism*; D014982:Xenopus laevis
C526365:6-(4-hydroxyphenyl)-2-thioxo-2,3-dihydro-4(1H)-pyrimidinone; D018528:ATP-Binding Cassette Transporters; D002457:Cell Extracts; D004268:DNA-Binding Proteins; C510917:Mre11 protein, Xenopus; C511600:NBN protein, Xenopus; D011744:Pyrimidinones; D013871:Thiones; D025521:Tumor Suppressor Proteins; D029867:Xenopus Proteins; D000076228:MRE11 Homologue Protein