Hepatitis B virus (HBV) expresses three co-terminal envelope proteins: large (L), middle (M), and small (S), with the S protein driving the secretion of both virions and subviral particles. Virion secretion requires N-linked glycosylation at N146 in the S domain but can be impaired by immune escape mutations. An M133T mutation creating a novel glycosylation site at N131could rescue virion secretion of N146Q mutant (loss of original glycosylation site) and immune escape mutants such as G145R. Here we demonstrate that other novel N-linked glycosylation sites could rescue virion secretion of the G145R and N146Q mutants to variable extents. Both G145R and N146Q mutations impaired vision secretion through the S protein. The M133T mutation restored vision secretion through the S protein, and could work in trans. Impaired virion secretion was not necessarily associated with a similar block in the secretion of subviral particles.
[1]Fudan Univ, Sch Basic Med Sci, Key Lab Med Mol Virol, Shanghai, Peoples R China;
[2]Brown Univ, Rhode Isl Hosp, Liver Res Ctr, Warren Alpert Sch Med, Providence, RI 02903 USA
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