FIG. 8.

No incorporation of HBV Pol harboring the cysteine mutation into nucleocapsid particles. (A) OptiPrep density gradient analysis was performed as detailed in Materials and Methods. HEK293 cells were cotransfected with the HBV Pol-null construct and either WT Pol or Pol mutant expression plasmid, as indicated. Three days following transfection, the cells were lysated with NP-40 lysis buffer, and the cell lysates were treated with proteinase K. Then, the lysates were subjected to a 10 to 50% OptiPrep density gradient. Fourteen 140-μl fractions from the top were collected, and HBV Pol and core proteins were detected by Western blot analysis with anti-Flag and anti-core antibodies, respectively. (B) Western blot (WB) analysis of the cell lysate was performed as described in the legend to Fig. 2B.