Sequence preference of 7,12-dimethylbenz[a]anthracene-syn-diol epoxide-DNA binding in the mouse H-ras gene detected by UvrABC nucleases.
We have found that 7,12-dimethylbenz[a]anthracene-syn-diol epoxide (syn-DMBADE)-modified DNA fragments are sensitive to UvrABC incision. The incisions occur mainly seven bases 5' and four bases 3' of a syn-DMBADE-modified adenine or guanine residue. The kinetics of UvrABC incision at different sequences in a DNA fragment are the same, and the extent of UvrABC incision is proportional to the syn-DMBADE concentration. On the basis of these results, we have concluded that UvrABC incision on syn-DMBADE-DNA adducts is independent of DNA sequence and is quantitative. Using the UvrABC incision method, we have analyzed the syn-DMBADE-DNA binding spectrum in several defined DNA fragments, including the first two exons of the mouse H-ras gene. We have found that both guanine and adenine residues in codons 12, 13, and 61 of the H-ras gene are strong syn-DMBADE binding sites. These results suggest that the initial binding of DMBADE may greatly contribute to the frequency of H-ras mutations. Results from dinucleotide binding analysis indicate that the 5'-nearest neighbor displays a greater effect on syn-DMBADE-DNA binding than the 3'-nearest neighbor.
Chen
J X
JX
Department of Carcinogenesis, University of Texas M. D. Anderson Cancer Center, Science Park-Research Division, Smithville 78957, USA.
Pao
A
A
Zheng
Y
Y
Ye
X
X
Kisleyou
A S
AS
Morris
R
R
Slaga
T J
TJ
Harvey
R G
RG
Tang
M S
MS
D015127:9,10-Dimethyl-1,2-benzanthracene / Q000031:analogs & derivatives / Q000378:metabolism; D000225:Adenine / Q000378:metabolism; D000818:Animals; D001665:Binding Sites; D003062:Codon; D018736:DNA Adducts / Q000737:chemistry / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D004706:Endodeoxyribonucleases / Q000378:metabolism*; D029968:Escherichia coli Proteins; D011905:Genes, ras / Q000235:genetics*; D006147:Guanine / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D051379:Mice; D015394:Molecular Structure
C059444:7,12-dimethylbenz(a)anthracene-DNA adduct; D003062:Codon; D018736:DNA Adducts; D029968:Escherichia coli Proteins; D015127:9,10-Dimethyl-1,2-benzanthracene; D006147:Guanine; D004706:Endodeoxyribonucleases; C036385:endodeoxyribonuclease uvrABC; D000225:Adenine