The Effect Of HBx And HBx Truncation And Ddb1on HBV Replication

Background: HBV replication is stimulated by the multifunctionalregulatory HBx protein. HBx interacts with several cellular proteins andmay mediate its role in HBV replication through these interactions. As themost important HBx binding partner, DDB1is required for HBVreplication. HBx is often deleted during the integration into host genomeand causes the HBx truncation. And HBV replication may be influenced bysome HBx truncations, especially COOH-terminal truncations. Howeverwhether HBx truncations influence HBV replication through stimulatingthe level of DDB1remains unknown.Objective: To investigate the effect of HBx and HBx truncations andDDB1on HBV replication.Methods: HepG2cells were transiently transfected or co-transfeced ofplasmid DNA. The level of DDB1was tested after72h by real timequantitive reverse transcription PCR and western blot analysis. The HBVDNA copies per cell were tested after72h by real time PCR. And the levelof HBsAg and HBeAg was tested by ELISA.Results: Replication from pHBVΔX was restored to wildtype pHBVlevels by co-transfection with pSI-X and pSI-x43-154, but not by co-transfection with pSI-X1-101. The level of DDB1was stimulated bypSI-X1-101, but not by pSI-x43-154.Besides the level of DDB1isapproximately parallel with the HBV DNA copies in HepG2cells.Conclusion: Both the the COOH-terminal amino acids of HBx andDDB1are required for HBV wildtype replication. HBV replication wasstimulated by HBx COOH-terminal truncation(HBx1-101)maybe throughstimulating the level of DDB1protein.