Figure 3.

Only the L protein interacts with the core protein. Huh7 cells were cotransfected by incubation for three days with a plasmid encoding the S-His or L-His protein together with a plasmid encoding the core protein. (A) Huh7 cells were fixed and double-stained with anti-HBs (in green) and anti-HBc (in red) antibodies, and the nuclei were counterstained with DAPI (in blue). Each image corresponds to the major phenotype observed. Note that the colocalization of envelope and core proteins was observed only for the L-His and core proteins. (B) Histogram of r values. Differences between L-His/Core and S-His/Core colocalizations were analyzed statistically by Mann-Whitney tests on 30 images from 3 different experiments (***p < 0.001). (C) Huh7 cell lysates were collected and 400 µg of total protein was subjected to IP with an anti-His antibody. Membranes were probed with an anti-HBs (IP) or an anti-HBc (Co-IP) antibody. Note that the co-IP of core protein was observed only in the presence of L-His protein.