Reduced secretion of virions and hepatitis B virus (HBV) surface antigen of a naturally occurring HBV variant correlates with the accumulation of the small S envelope protein in the endoplasmic reticulum and Golgi apparatus

Pong Kian Chua, Robert Yung Liang Wang, Min Hui Lin, Tetsuya Masuda, Fat Moon Suk, Chiaho Shih

研究成果: 雜誌貢獻文章同行評審

63 引文 斯高帕斯(Scopus)

摘要

We identified two novel naturally occurring mutations (W74L and L77R) in the small S envelope protein of hepatitis B virus (HBV). Mutation L77R alone resulted in > 10-fold-reduced secretion of virions. In addition, the 2.8-fold reduction of the extracellular HBV surface antigen (HBsAg) of mutant L77R from transfected Huh7 cells appeared to be correlated with a 1.7-fold reduction of intracellular HBsAg, as measured by enzyme-linked immunosorbent assay (ELISA). Surprisingly, opposite to the ELISA results, Western blot analysis revealed a near-10-fold-increased level of the intracellular mutant small S envelope protein. The discrepancy between ELISA and Western blot data was due to significant accumulation of the mutant L77R HBsAg in the intracellular pellet fraction. In contrast to HBsAg, the secretion of HBeAg was normal in L77R-transfected cells. The wild-type HBsAg was usually more diffuse and evenly distributed in the cytoplasm, often outside the perinuclear endoplasmic reticulum (ER) and Golgi apparatus, as observed by immunofluorescence assay. In contrast, the L77R mutant HBsAg tends to be highly restricted within the ER and Golgi, often accumulated in the Golgi compartments distal from the nucleus. The almost exclusive retention in the ER-Golgi of L77R HBsAg was similar to what was observed when the large envelope protein was overexpressed. These multiple aberrant phenotypes of mutant L77R can be corrected by a second naturally occurring S envelope imitation, W74L. Despite the accumulation of L77R HBsAg in ER-Golgi of transfected Huh7 cells, we detected no increase in Grp78 mRNA and proteins, which are common markers for ER stress response.

原文英語
頁(從 - 到)13483-13496
頁數14
期刊Journal of Virology
79
發行號21
DOIs
出版狀態已發佈 - 11月 2005

ASJC Scopus subject areas

  • 微生物學
  • 免疫學
  • 昆蟲科學
  • 病毒學

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