EFFECT OF HEPATITIS B VIRUS CORE PROMOTER GENE HETEROGENEITY ON ITS TRANSCRIPTIONAL ACTIVITY / 解放军医学杂志

ABSTRACT

Polymerase chain reaction was employed to amplify the whole HBV CP region from the serum of patients with chronic hepatitis B virus(HBV) infection, and then the PCR products were subcloned into pGEM Teasy vectors. Clones were randomly selected to be sequenced and the selected clones were compared to look for the difference.The sequencing results suggested that each sequence of selected clones was different and there were HBV quasispecies groups in patients. There were hot deletion region and point mutation near the TATA like box of CP gene. To address whether the mutations were responsible for the transcriptional activity, the wild type(wt) and the mutants of HBV CP genes were subcloned into pcDNA3 1( ) vectors, respectively. The reverse oriented clones were digested with KpnI and XhoI, and cloned into the KpnI and XhoI sites of the chloramphenicol acetyltransferase (CAT) expressing vector (pCAT3 basic).The recombinant CAT plasmids were transfected into HepG2 cells using lipofectamine PLUS reagent, and the CAT expression which indirectly represented the transcriptional activity of HBV CP lying upstream of CAT gene was detected with a CAT ELISA kit. The restriction enzyme digesting results indicated that the recombinant CAT plasmids were successfully constructed, and the transfection tests indicated that the transcriptional activity of the mutants with deletion or substitute point mutation of TATA like box were reduced in comparison with that of CPwt. The HBV CP gene heterogeneity downregulated the transcriptional activity to some extent.