Effect of aflatoxin B1-8,9-epoxide-DNA adducts on transcription of a supF gene fragment.
A linearized template, obtained from the vector pGEM-3Zf(+) containing a supF gene fragment, was treated with aflatoxin B1-8,9-epoxide (AFB1 epoxide) and transcription in vitro was then studied. The template functions of both strands of the supF gene were similarly inhibited as shown by transcription with both T7 and SP6 RNA polymerases. This inhibition was dose-dependent and affected the elongation step more extensively than the initiation step. Gel electrophoretic analysis of RNA formed by T7 RNA polymerase indicated that template treated with different AFB1 epoxide doses yielded the same three major truncated RNA fragments. Sequence analysis showed that these major sites of RNA truncation occurred in the vicinity of adjacent guanine residues in the template.
Yu
F L
FL
Chemistry of Carcinogenesis Laboratory, NCI-Frederick Cancer Research and Development Center, MD 21702, USA.
Cahill
J M
JM
Lipinski
L J
LJ
Dipple
A
A
D016604:Aflatoxin B1 / Q000031:analogs & derivatives* / Q000138:chemical synthesis / Q000378:metabolism / Q000494:pharmacology; D001483:Base Sequence; D018736:DNA Adducts / Q000378:metabolism*; D012321:DNA-Directed RNA Polymerases / Q000187:drug effects / Q000378:metabolism; D004121:Dimethyl Sulfoxide / Q000494:pharmacology; D016153:Genes, Suppressor; D005822:Genetic Vectors / Q000235:genetics; D008969:Molecular Sequence Data; D012313:RNA / Q000096:biosynthesis*; D012343:RNA, Transfer / Q000235:genetics*; D014158:Transcription, Genetic / Q000187:drug effects*; D014764:Viral Proteins
D018736:DNA Adducts; D014764:Viral Proteins; C096275:supF tRNA; C006426:aflatoxin B1-2,3-oxide; D012313:RNA; D012343:RNA, Transfer; D016604:Aflatoxin B1; C070852:RNA polymerase SP6; C062210:bacteriophage T7 RNA polymerase; D012321:DNA-Directed RNA Polymerases; D004121:Dimethyl Sulfoxide