LIG3 and infection: Upon infection, the levels of HBV cccDNA and core protein were markedly lower in HepG2-NTCP cells with LIG1 or LIG3 knock-down compared to the control knock-down cells (Fig 6B, 6C and 6D), suggesting that LIG1 and LIG3 are also required for the first round HBV cccDNA formation during de novo infection.