Analysis of point mutations in HPRT mutant T-lymphocytes derived from coke-oven workers.
We studied mutations in exon 3 of the hypoxanthine-guanine phosphoribosyltransferase (HPRT) locus in 113 6-thioguanine-resistant T-cell clones derived from coke-oven workers and control subjects in order to analyse possible changes in the mutational spectrum associated with the exposure to polycyclic aromatic hydrocarbons (PAHs). In 99 mutants, HPRT exon 3 was analysed by means of genomic polymerase chain reaction (PCR) and single-strand conformation polymorphism (SSCP). Products for which SSCP indicated the presence of a mutation were further analysed by DNA sequencing. In addition, HPRT cDNA from 14 clones was analysed by reverse transcription (RT) PCR and DNA sequencing. In total, 18/113 mutants (16%) had a mutation in exon 3. This frequency was similar in PAH-exposed (9/57) and non-exposed (9/56) subjects. Base substitutions caused 14 mutations at 13 different sites. Three +/- 1 bp frameshifts and one 6 bp deletion were identified. No significant differences between PAH-exposed and non-exposed workers were observed in this limited mutational spectrum. These results indicate that deletions/insertions at the HPRT exon 3 account for 22% of the mutations, and base substitutions for 78%.
Mognato
M
M
Department of Biology, University of Padova, Italy.
Graziani
M
M
Celotti
L
L
D000395:Air Pollutants, Occupational / Q000633:toxicity; D004252:DNA Mutational Analysis; D018076:DNA, Complementary / Q000235:genetics; D006801:Humans; D007041:Hypoxanthine Phosphoribosyltransferase / Q000187:drug effects* / Q000235:genetics*; D008669:Metallurgy; D009152:Mutagenicity Tests; D016273:Occupational Exposure; D017354:Point Mutation; D011084:Polycyclic Aromatic Hydrocarbons / Q000633:toxicity; D018807:Polymorphism, Single-Stranded Conformational; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013601:T-Lymphocytes / Q000187:drug effects / Q000502:physiology*; D013866:Thioguanine / Q000633:toxicity
D000395:Air Pollutants, Occupational; D018076:DNA, Complementary; D011084:Polycyclic Aromatic Hydrocarbons; D007041:Hypoxanthine Phosphoribosyltransferase; D013866:Thioguanine