FIG. 2.

Influence of C mutations on virion formation. Several point mutations, indicated in single-letter code, were introduced at selected positions in CP. After cotransfection of Huh7 cells with a core-negative HBV genome and the expression vector for the core derivative (Fig. 1), cytoplasmic nucleocapsids (bottom) and virions from the culture medium (top) were immunoprecipitated with anti-HBc and anti-HBs, respectively. The viral genome was radioactively labeled by EPR, isolated, and visualized by agarose gel electrophoresis and autoradiography. (A) Mutations at positions where alanine mutations allowed capsid formation and HBV genome synthesis but blocked virion formation. Almost all mutations at S17, K96, and I126 reproduced this phenotype. (B) Mutations at positions where alanine mutations were WT. Almost all mutations at these positions were also WT. Controls included cotransfection with the WT core gene (WT), transfection with the genomic core-negative HBV construct alone (C⁻), and 1 μl of a highly viremic serum from a human HBV carrier used for EPR (s).