FIG. 3.

Deficiency of intracellular HBV DNA synthesis is found in the ayw codon 97 mutants but not in the adr counterparts. HBV subtype adr or ayw core particle-associated DNA was harvested 7 days after transfection of human hepatoma Huh7 or HepG2 cells, respectively, and analyzed by Southern blot analysis using a plus-strand-specific riboprobe (upper panel). Following removal of the plus strand-specific riboprobe, the same filter was rehybridized with a minus-strand-specific riboprobe (lower panel). Intracellular core particle-associated HBV DNA was purified with or without micrococcal nuclease or restriction enzyme DpnI treatment (+MN/−DpnI versus −MN/+DpnI). The DpnI treatment can selectively digest the methylated input plasmid DNA originated from bacteria but not the de novo-synthesized HBV DNA originated from transfected hepatoma cells. DpnI-digested plasmid DNA is indicated by ∗.