Down-regulatinq effect of orosomucoid 2 on preS1 promoter of hepatitis B virus

AIM: To investigate activity of orosomucoid 2 (ORM2) on preS1 promoter (SP I) of hepatitis B virus (HBV). METHODS: Yeast one-hybrid system was employed in screening of DNA-binding proteins specifically recognizing HBV-SP I sequence, in which ORM2 was identified in GenBank by bioinformatics. For further studying the interaction between ORM2 and HBV-SP I, the sequence of ORM2 was amplified from HepG2 genome by polymerase chain reaction (PCR) technique, which was then cloned into pcDNA3.1(-) expression vector. The HepG2 cell line was transfected by pCAT3- SP I, and co-transfected by pCAT3-SP I and pcDNA3.1(-)-ORM2, respectively. The chloramphenicol acetyltransferase (CAT) activity was detected by an enzyme-linked immunosorbent assay (ELISA) kit. RESULTS: pCAT3-SP I had higher activity of CAT than pCAT3-basic by ELISA kit. The expression of CAT from pCAT3-SP I was increased 81.9%, as compared with that in the co-transfection of pCAT3-SP I and pcDNA3.1(-)-ORM2. CONCLUSION: Cell transfection and ELISA technology are successfully used to prove the results from yeast one-hybrid system, which brings some new clues for studying the specific binding proteins of HBV- SP I and its transcriptional regulation mechanism.