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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
10
pubmed:dateCreated
1993-12-1
pubmed:abstractText
6-Nitrochrysene can be activated to genotoxic derivatives by two major metabolic pathways: nitroreduction to N-hydroxy-6-aminochrysene, and a combination of ring-oxidation and nitroreduction that involves the intermediate formation of trans-1,2-dihydro-1,2-dihydroxy-6-aminochrysene (6-AC-1,2-dihydrodiol). The DNA adduct formed from this latter pathway was evaluated by reacting individual deoxynucleoside 5'-monophosphates with 6-AC-1,2-dihydrodiol in the presence of liver microsomal enzymes from 3-methylcholanthrene-pretreated rats. Binding was greatest to deoxyguanosine monophosphate and the major deoxyguanosine (dG) adduct co-chromatographed with the single major adduct formed from the microsome-catalyzed reaction of 6-AC-1,2-dihydrodiol with DNA. In order to characterize the mutational changes associated with the 6-AC-1,2-dihydrodiol pathway, we analyzed the mutational spectrum produced by 6-AC-1,2-dihydrodiol in the hypoxanthine-guanine phosphoribosyltransferase (hprt) gene of CHO-K1 cells. cDNA was synthesized from the RNA of 28 6-thioguanine-resistant mutants, the hprt coding region amplified by the polymerase chain reaction, and the DNA products directly sequenced. Twenty independent primary mutations were found: 12 G:C-->T:A transversions, three G:C-->C:G transversions, one G:C-->A:T transition, one A:T-->T:A transversion, two -1 frameshift mutations in sequences containing consecutive guanines, and one 11 bp deletion. All G:C basepair substitutions had the mutated dG on the non-transcribed strand and 86% of the G:C basepair substitutions had one purine 3' to the mutated dG. The pattern of 6-AC-1,2-dihydrodiol-induced basepair substitutions was distinct from the pattern observed in solvent control mutants. These results are consistent with the formation of a promutagenic dG adduct from a metabolite of 6-AC-1,2-dihydrodiol.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Oct
pubmed:issn
0143-3334
pubmed:author
pubmed:issnType
Print
pubmed:volume
14
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
2109-14
pubmed:dateRevised
2005-11-17
pubmed:meshHeading
pubmed:year
1993
pubmed:articleTitle
Trans-1,2-dihydro-1,2-dihydroxy-6-aminochrysene is metabolized to form a major adduct with deoxyguanosine and produces mutations in the hprt gene of Chinese hamster ovary cells at G:C basepairs.
pubmed:affiliation
Division of Biochemical, National Center for Toxicological Research, Jefferson, AR 72079.
pubmed:publicationType
Journal Article