Abstract: BACKGROUND ＆ AIM： To investigate the effects of the untreated water and chlorinated drinking water extracts of the Han River on DNA damage and the expression of the gadd153 promoter and mRNA. MATERIAL AND METHODS： The DNA damage was assessed by the alkaline comet assay. The plasmid(pGADD153-Luc)containing DNA damage and repair inducible gene 153 (gadd153) promoter and luciferase reporter gene were constructed. The activity of gadd153 promoter was represented by the luciferase activity, and the inducible luciferase activity was detected by bioluminescence. The expression of gadd153 mRNA was detected by RT-PCR. RESULTS： The Olive Tail Moment(OTM) induced by the untreated water and chlorinated drinking water extracts was increased at the dose of 10, 100ml/ml medium (P<0.01), compared with control. There was a good dose-response relationship (r=0.882, P<0.05; r=0.940, P<0.05); The OTM induced by the chlorinated drinking water extracts was higher than that of untreated water (P<0.05). The luciferase activity was significantly increased in each treatment group at each dose (P<0.01) and there were a good dose-response relationship (r=0.814, P<0.05; r=0.921, P<0.05). There were positive correlations between the OTM and the luciferase activities (r=0.980, P<0.01, r=0.995, P<0.01); The high expression of gadd153 mRNA was induced by the water extracts at dose of 100 ml/ml medium (P<0.05). There werepositive correlation between the OTM and the expressions of gadd153 mRNA (r=0.864, P<0.05; r=0.897, P<0.05). CONCLUSION： The untreated water and chlorinated drinking water extracts of Han River could induce DNA damage and further activated the gadd153 promoter which regulated the expression of gadd153 mRNA.

Key words: untreated water and chlorinated drinking water extracts, DNA damage, gadd153 promoter, gadd153, luciferase reporter gene