Identification of a deletion in the mismatch repair gene, MSH2, using mouse-human cell hybrids monosomal for chromosome 2.
Hereditary non-polyposis colorectal cancer is characterized by mutations in one of the DNA mismatch repair genes, primarily MLH1, MSH2, or MSH6. We report here the identification of a genomic deletion of approximately 11.4 kb encompassing the first two exons of the MSH2 gene in two generations of an Ohio family. By Southern blot analysis, using a cDNA probe spanning the first seven exons of MSH2, an alteration in each of three different enzyme digests (including a unique 13-kb band on HindIII digests) was observed, which suggested the presence of a large alteration in the 5' region of this gene. Mouse-human cell hybrids from a mutation carrier were then generated which contained a single copy each of human chromosome 2 on which the MSH2 gene resides. Southern blots on DNA from the cell hybrids demonstrated the same, unique 13-kb band from one MSH2 allele, as seen in the diploid DNA. DNA from this same monosomal cell hybrid failed to amplify in polymerase chain reactions (PCRs) using primers to exons 1 and 2, demonstrating the deletion of these sequences in one MSH2 allele, and the breakpoints involving Alu repeats were identified by PCR amplification and sequence analysis.
Pyatt
R E
RE
Department of Pathology, Ohio State University, Columbus, Ohio, USA. rpyatt@emory.edu
Nakagawa
H
H
Hampel
H
H
Sedra
M
M
Fuchik
M B
MB
Comeras
I
I
de la Chapelle
A
A
Prior
T W
TW
D000818:Animals; D001345:Autoradiography; D020137:Base Pair Mismatch / Q000235:genetics*; D015139:Blotting, Southern; D002889:Chromosomes, Human, Pair 2 / Q000235:genetics*; D003123:Colorectal Neoplasms, Hereditary Nonpolyposis / Q000235:genetics*; D004260:DNA Repair / Q000235:genetics*; D005091:Exons / Q000235:genetics; D005260:Female; D017353:Gene Deletion; D006801:Humans; D006822:Hybrid Cells; D008297:Male; D051379:Mice; D009820:Ohio; D010375:Pedigree; D017422:Sequence Analysis, DNA