Development and characterization of a 293 cell line with regulatable expression of the hepatitis B virus large envelope protein.
During the life cycle of hepatitis B virus (HBV) the large L envelope protein plays a pivotal role that is related to its peculiar dual transmembrane topology. To study the complex structure and diverse functions of L under regulated conditions of production, a human 293 cell line stably expressing L under the control of the ecdysone-inducible promoter was generated. Cells demonstrated stringent dose- and time-dependent kinetics of induction with undetectable background expression in the absence of the inducer. Temporal control of L expression allowed to trace (i) its posttranslational reorientation resulting in the mixed topology; (ii) its spatial redistribution from the endoplasmic reticulum to Golgi-like structures; and (iii) its intracellular retention in a membrane-associated configuration. On regulated overproduction, L blocked the secretion of HBV small envelope polypeptides without impairing the cell secretory apparatus. Despite the continuous high-level storage of L within the 293 cell line, no cytopathic effects could be detected. This is in contrast to ground-glass hepatocytes of chronic HBV carriers and HBV transgenic mice and may imply that the intracellular storage of L is particularly damaging to the liver cell.
Lambert
Carsten
C
Department of Medical Microbiology and Hygiene, University of Mainz, Augustusplatz, 55101 Mainz, Germany.
Prange
Reinhild
R
D002461:Cell Line, Transformed / Q000378:metabolism*; D002462:Cell Membrane / Q000378:metabolism; D004440:Ecdysone / Q000494:pharmacology; D004721:Endoplasmic Reticulum / Q000378:metabolism; D015967:Gene Expression Regulation, Viral / Q000187:drug effects; D006056:Golgi Apparatus / Q000378:metabolism; D006801:Humans; D011401:Promoter Regions, Genetic / Q000187:drug effects; D011487:Protein Conformation; D014759:Viral Envelope Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
C096362:L protein, hepatitis B virus; D014759:Viral Envelope Proteins; D004440:Ecdysone