Objective:To investigate the regulation of hepatitis C virus core protein(HCV core)on E-cadherin promoter activity.Methods:The CDH1 promoter fragment

amplified from the Huh7 cells

was cloned into pGL3-Basic to construct the luciferase report plasmid(pGL3-CDH1). The three E-boxes consensus sequences

which located at-80~-75 nt(E-box1)

-30~-25 nt(E-box3)

and+22~+27 nt(E-box4)in human E-cadherin promoter region

play important role in E-cadherin transcriptional regulation. Thus

mutagenic primers were designed to induce point mutations in three putative E-box sites in the CDH1 promoter sequence. These mutations changed the sequence of the E-boxes from 5’-CANNTG-3’to 5’-AANNTA-3’

which resulted in the insertion of a Snailunrecognized site. These reporter constructs were named E-box1(pGL3-mut1)

E-box3(pGL3-mut2)

E-box4(pGL3-mut3)single mutation types and E-box1+3(pGL3-mut1+2)

E-box1+4(pGL3-mut1+3)

E-box3+4(pGL3-mut2+3)

E-box1+3+4(pGL3-mut1+2+3) mutant constructs respectively. The E-cadherin promoter constructs containing wild-type or mutant E-boxes were co-transfected with p RL-TK(an internal control) into SMMC-7721 cells over expressing HCV core protein respectively

then the luciferase activities were detected. Results:Compared with that of GFP control group

HCV core protein could significantly inhibit wild-type CDH1 promoter activity. In E-box single mutant CDH1 transfection cells

the inhibition of HCV core protein on CDH1 promoter decreased in different degrees. It is most obvious in-80~-75 nt and-30~-25 nt. In compound mutation of CDH1-transfected cells

the HCV core-induced CDH1 inhibition was significantly diminished. Conclusion:HCV Core protein strongly inhibits E-cadherin transcriptional activity. The-80~-75 nt

-30~-25 nt E-boxes consensus sequences within E-cadherin promoter region may play a dominant role in HCV core-induced E-cadherin repression.