Polycyclic aromatic hydrocarbons(PAHs),dimethyl beazanthracene(DMBA)and benzo-(a)-pyrene(BaP),stimulate the expression of the P1-450 gene in human lung tumor cells(ChaGo)in culture.A concentration-and time-dependent i...Polycyclic aromatic hydrocarbons(PAHs),dimethyl beazanthracene(DMBA)and benzo-(a)-pyrene(BaP),stimulate the expression of the P1-450 gene in human lung tumor cells(ChaGo)in culture.A concentration-and time-dependent increase in the level of P1-450 specific mRNA sequences hasbeen observed in ChaGo cells treated with sublethal concentrations of DMBA.Results presentedsuggest that the parent compound causes the induction of P1-450 gene expression.The methylationpattern of the internal“-C-” residues of the “-CCGG-” sequence has been studied in a stretch ofabout 8000 base pairs(bp)of DNA sequence in and around the P1-450 gene in the control andDMBA-treated ChaGo cells.A comparative Southern blot analysis of the Msp Ⅰ/Hpa Ⅱ digestedDNA of the control and DMBA-treated ChaGo cells followed by hybridization with ^(32)P-labelledregion-specific probes,revealed that i)the internal “-C-” residues of the “-CCGG-” sequences ofdifferent regions of P1-450 gene were methylated to different degrees;ii)DMBA treatment of thecells induced hypomethylation of only the 5' end “-CCGG-” sequences of the gene;and iii)themethylation patterns of “-CCGG-” sequences of most of the coding region and of the 3' end regionof P1-450 gene were not affected by such DMBA treatment.展开更多
基金This work is supported by grant(HL32034) from the U.S.National Institute of Heart,Lung and Blood.
文摘Polycyclic aromatic hydrocarbons(PAHs),dimethyl beazanthracene(DMBA)and benzo-(a)-pyrene(BaP),stimulate the expression of the P1-450 gene in human lung tumor cells(ChaGo)in culture.A concentration-and time-dependent increase in the level of P1-450 specific mRNA sequences hasbeen observed in ChaGo cells treated with sublethal concentrations of DMBA.Results presentedsuggest that the parent compound causes the induction of P1-450 gene expression.The methylationpattern of the internal“-C-” residues of the “-CCGG-” sequence has been studied in a stretch ofabout 8000 base pairs(bp)of DNA sequence in and around the P1-450 gene in the control andDMBA-treated ChaGo cells.A comparative Southern blot analysis of the Msp Ⅰ/Hpa Ⅱ digestedDNA of the control and DMBA-treated ChaGo cells followed by hybridization with ^(32)P-labelledregion-specific probes,revealed that i)the internal “-C-” residues of the “-CCGG-” sequences ofdifferent regions of P1-450 gene were methylated to different degrees;ii)DMBA treatment of thecells induced hypomethylation of only the 5' end “-CCGG-” sequences of the gene;and iii)themethylation patterns of “-CCGG-” sequences of most of the coding region and of the 3' end regionof P1-450 gene were not affected by such DMBA treatment.
