trans-Complementation of HBV rtM204I mutant replication by HBV wild-type polymerase

Abstract

The function of the hepatitis B virus (HBV) wild-type (WT) polymerase (pol) expressed alone or in the context of the intact genome when interacting with HBV rtM204I in HepG2 cells was compared. We show that WT pol expression from a packaging-defective RNA can complement defective rtM204I pol activity resulting in increased levels of HBV replicative intermediates (RI). Analysis of the genetically marked genomes showed that this restoration resulted from trans-complementation, rather than recombination. In contrast, we demonstrate that enhanced levels of total HBV RI observed when cells were cotransduced with both WT and rtM204I baculoviruses were predominantly WT RI. In this case, WT pol was produced from a full-length pregenomic RNA (pgRNA). We conclude that the WT pol has the capacity to trans-complement the replication defect of rtM204I; however, when expressed from an authentic pgRNA, in a mixed infection, WT pol may not trans-complement efficiently.

A novel method for the analysis of drug-resistant phenotypes of hepatitis B virus

“…Due to the advantage of competitive replication, mutants with higher fitness levels may predominate in the total population and may differ in changing environments, such as the immune state of patients and treatment with interferon or NAs. As shown in previous studies, non-replicate HBV-RT mutations can be rescued by eukaryotic expression plasmids of HBV polymerase (27,28). In HBV quasispecies, it is unclear whether mutants with low replication capacity may be restored by a polymerase produced by mutants with normal replication capacities.…”