An Msh2 point mutation uncouples DNA mismatch repair and apoptosis.
Mutations in the human DNA mismatch repair gene MSH2 are associated with hereditary nonpolyposis colorectal cancer as well as a significant proportion of sporadic colorectal cancer. The inactivation of MSH2 results in the accumulation of somatic mutations in the genome of tumor cells and resistance to the genotoxic effects of a variety of chemotherapeutic agents. Here we show that the DNA repair and DNA damage-induced apoptosis functions of Msh2 can be uncoupled using mice that carry the G674A missense mutation in the conserved ATPase domain. As a consequence, although Msh2(G674A) homozygous mutant mice are highly tumor prone, the onset of tumorigenesis is delayed as compared with Msh2-null mice. In addition, tumors that carry the mutant allele remain responsive to treatment with a chemotherapeutic agent. Our results indicate that Msh2-mediated apoptosis is an important component of tumor suppression and that certain MSH2 missense mutations can cause mismatch repair deficiency while retaining the signaling functions that confer sensitivity to chemotherapeutic agents.
Lin
Diana P
DP
Department of Cell Biology, Albert Einstein College of Medicine, Bronx, New York, USA.
Wang
Yuxun
Y
Scherer
Stefan J
SJ
Clark
Alan B
AB
Yang
Kan
K
Avdievich
Elena
E
Jin
Bo
B
Werling
Uwe
U
Parris
Tchaiko
T
Kurihara
Naoto
N
Umar
Asad
A
Kucherlapati
Raju
R
Lipkin
Martin
M
Kunkel
Thomas A
TA
Edelmann
Winfried
W
D000409:Alanine; D019943:Amino Acid Substitution; D000818:Animals; D017209:Apoptosis / Q000235:genetics*; D020137:Base Pair Mismatch / Q000235:genetics; D022202:Chromosomes, Artificial, Bacterial; D002945:Cisplatin / Q000633:toxicity; D003062:Codon / Q000235:genetics; D004249:DNA Damage / Q000235:genetics; D004260:DNA Repair / Q000235:genetics*; D004268:DNA-Binding Proteins; D005347:Fibroblasts / Q000502:physiology; D005998:Glycine; D051379:Mice; D051718:MutS Homolog 2 Protein; D017354:Point Mutation; D011518:Proto-Oncogene Proteins / Q000235:genetics*; D017384:Sequence Deletion
D003062:Codon; D004268:DNA-Binding Proteins; D011518:Proto-Oncogene Proteins; C497173:Msh2 protein, mouse; D051718:MutS Homolog 2 Protein; D000409:Alanine; D002945:Cisplatin; D005998:Glycine