Faculty Collaboration Database

The mutational spectrum of the HPRT gene from human T cells in vivo shares a significant concordant set of hot spots with MNNG-treated human cells. Cancer Res 2003 Sep 15;63(18):5793-8

Date

10/03/2003

Pubmed ID

14522901

Scopus ID

2-s2.0-0141731313 (requires institutional sign-in at Scopus site)   11 Citations

Abstract

The preponderance of G:C to A:T transitions in inherited and somatic human mutations has led to the hypothesis that some of these mutations arise as a result of formation of O(6)-methylguanine in DNA. To test this hypothesis, the fine structure map of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG)-induced mutations was determined in human lymphoblastoid cells in the human hypoxanthine-guanine-phosphoribosyltransferase (HPRT) gene and compared with HPRT mutations observed in somatic T lymphocytes from normal individuals. Human TK6 cells, which are methylguanine methyltransferase deficient (MGMT(-)), were treated with the methylating agent MNNG to create a level of O(6)-methylguanine in cellular DNA equal to that found in normal human tissues. A total of 676 bp of the HPRT gene was scanned using constant denaturing capillary electrophoresis and high-fidelity PCR. MNNG induced 14 predominant hot spots, all which were G:C to A:T transitions. Thirteen of these 14 MNNG-induced hot spots were found among the in vivo set, and 10 of the MNNG-induced hot spots were among 75 putative in vivo hot spots (mutations observed two or more times in vivo). Using a hypergeometric test for concordance, the MNNG-induced hot spots were found to be a significant subset of the putative in vivo hot spots (P < 4 x 10(-7)). The set of shared hot spots comprise some 18% of the HPRT in vivo hot spot spectrum and strongly suggest that MNNG-induced hot spots in vitro share a common mutational pathway with a significant subset of somatic mutations in vivo.

Author List

Tomita-Mitchell A, Ling LL, Glover CL, Goodluck-Griffith J, Thilly WG

Author

Aoy Tomita Mitchell PhD Professor in the Surgery department at Medical College of Wisconsin

MESH terms used to index this publication - Major topics in bold

Cell Survival
Cells, Cultured
DNA Mutational Analysis
Exons
Guanine
Humans
Hypoxanthine Phosphoribosyltransferase
Methylnitronitrosoguanidine
Mutation
O(6)-Methylguanine-DNA Methyltransferase
T-Lymphocytes