HBV genome organization. The partially double-stranded, circular RC-DNA is indicated by thick black lines, with P covalently linked to the 5´ end of the (-)-DNA, and the RNA primer (zigzag line) at the 5´ end of (+)-DNA. The dashed part symbolizes the heterogeneous lengths of the (+)-strands. DR1 and DR2 are the direct repeats. The outer circle symbolizes the terminally redundant pgRNA with ε close to the 5´ end, and the poly-A tail at the 3´ end. The precore mRNA is nearly identical, except it starts slightly upstream. The relative positions of the open reading frames for core (C), P, preS/S, and X are shown inside. TP, Terminal protein domain of P.