Abstract: Objective: to analyze the modulating mechanism of estrogen on different fractions of apo A? gene promoter. Methods: Construct recombinants containing different length DNA fragments of apo AI gene (-41/+397, -256/+397, and -2500/+397) with or without a 7-kb region apo CIII/AIV intergenic region in basic pGL2 vector that containing lueiferase reporter gene. The final recombinants with the internal control vector pRL-null with renilla luciferase reporter gene were transfected to HepG2 cells by the cationic lipid method. After 24h, the cells were treated with estradiol at 10μmol/L concentration; After 48h, cells were collected and lysized. The activities of these luciferase enzymes were measured with Dual-GloTM Luciferase Assay System. Results: In estradiol induced experiments, exception of the recombinant plasmids containing only the basal promoter (-41/+397bp) with or without region of apo CIII/AIV, The all recombinants expression of luciferase enzymes was great increased. There was no different between pGL2/-41AⅠand pGL2/-41AⅠCⅢAⅣ in the presence of estradiol. Conclusion: Promoter area containing -256bp may be the smallest reactive element for estrogen. It can increase transcription activity after stimulating by estrogen. The apoCIII/AIV gene modulating was not affected by estrogen.

Key words: estrogen, apolipoprotein AⅠ, gene transcription modulation