title: Regulatory Effect of HBV Integrated Fragment on PCNA Promoter.
abstract: H7C is a HBV integrated fragment isolated from a human hepatocellular carcinoma, containing the promoter of preS2 and the C-terminal truncated preS/S open reading frame. We have studied the effect of the 3'-truncated preS/S on human proliferating cell nuclear antigen (PCNA) promoter by co-transfection of the expression plasmids. Result showed that the product, pKSH7C-Hpa I, which contained the intact H7C and the flanking cellular sequences, stimulated the expression from PCNA promoter dose-dependently, and its effect was 1-2 folds higher than that on SV40 promoter. However, two subclones, pKSH7C-XHX and pKSH7C-XbH, which would not express preS/S, showed no stimulatory effect. Furthermore, when if the -45 bp ATF-like site was mutated, the activation effect became diminished. This showed that the ATF-like site might be important in mediating the transactivating process. This is the first report of the effect of a HBV integrated fragment on the promoter of a replicating protein factor.
authors.affiliation: Shanghai Institute of Biochemistry, the Chinese Academy of Sciences, Shanghai 200031, China.
authors.forename: Ming
authors.initials: M
authors.lastname: Li
authors.forename: Lei
authors.initials: L
authors.lastname: Wang
authors.forename: Hai-Ying
authors.initials: HY
authors.lastname: Qiu
authors.forename: Yu-Zhong
authors.initials: YZ
authors.lastname: Zhou
authors.forename: Chang-De
authors.initials: CD
authors.lastname: Lu