title: Characterization of TCHQ-induced genotoxicity and mutagenesis using the pSP189 shuttle vector in mammalian cells.
abstract: Tetrachlorohydroquinone (TCHQ) is a major toxic metabolite of the widely used wood preservative, pentachlorophenol (PCP), and it has also been implicated in PCP genotoxicity. However, the underlying mechanisms of genotoxicity and mutagenesis induced by TCHQ remain unclear. In this study, we examined the genotoxicity of TCHQ by using comet assays to detect DNA breakage and formation of TCHQ-DNA adducts. Then, we further verified the levels of mutagenesis by using the pSP189 shuttle vector in A549 human lung carcinoma cells. We demonstrated that TCHQ causes significant genotoxicity by inducing DNA breakage and forming DNA adducts. Additionally, DNA sequence analysis of the TCHQ-induced mutations revealed that 85.36% were single base substitutions, 9.76% were single base insertions, and 4.88% were large fragment deletions. More than 80% of the base substitutions occurred at G:C base pairs, and the mutations were G:C to C:G, G:C to T:A or G:C to A:T transversions and transitions. The most common types of mutations in A549 cells were G:C to A:T (37.14%) and A:T to C:G transitions (14.29%) and G:C to C:G (34.29%) and G:C to T:A (11.43%) transversions. We identified hotspots at nucleotides 129, 141, and 155 in the supF gene of plasmid pSP189. These mutation hotspots accounted for 63% of all single base substitutions. We conclude that TCHQ induces sequence-specific DNA mutations at high frequencies. Therefore, the safety of using this product would be carefully examined.
authors.affiliation: State Key Laboratory of Environmental Chemistry and Ecotoxicology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing, PR China. avaecn@gmail.com
authors.forename: Jing
authors.initials: J
authors.lastname: Wang
authors.forename: Shouyi
authors.initials: S
authors.lastname: Yu
authors.forename: Shouhai
authors.initials: S
authors.lastname: Jiao
authors.forename: Xiaowen
authors.initials: X
authors.lastname: Lv
authors.forename: Min
authors.initials: M
authors.lastname: Ma
authors.forename: Ben-Zhan
authors.initials: BZ
authors.lastname: Zhu
authors.forename: Yuguo
authors.initials: Y
authors.lastname: Du
mesh_terms: D000818:Animals; D001483:Base Sequence; D045744:Cell Line, Tumor; D002522:Chlorocebus aethiops; D020552:Comet Assay / Q000379:methods; D018736:DNA Adducts / Q000187:drug effects; D004249:DNA Damage / Q000187:drug effects*; D005822:Genetic Vectors; D006801:Humans; D006873:Hydroquinones / Q000633:toxicity*; D008969:Molecular Sequence Data; D016296:Mutagenesis / Q000187:drug effects*; D010957:Plasmids; D017354:Point Mutation; D017422:Sequence Analysis, DNA; D017384:Sequence Deletion; D014162:Transfection; D014709:Vero Cells
chemical_list: D018736:DNA Adducts; D006873:Hydroquinones; C044578:2,3,5,6-tetrachlorohydroquinone