The proteins of hepatitis B dane particle cores

Abstract

Although several studies have been done to analyze the peptides of purified 22-nm HbsAg particles, no information has been published about the peptides of the core of the Dane particle which bears the other hepatitis B viral antigen. HbcAg. Dane particles and Dane particle cores (produced by NP-40 treatment of Dane particles) were purified by equilibrium centrifugation in CsCl density gradients. Two populations of Dane particles were observed at densities 1.27 and 1.24 g/ml, respectively. The higher buoyant density Dane particles yielded exclusively cores of buoyant density 1.38 g/ml in CsCl, and the lower buoyant density Dane particles yielded two kinds of cores with buoyant densities of 1.38 and 1.325 g/ml, respectively. Only the higher density Dane particles and cores manifested endogenously primed DNA polymerase activity. The peptides of density 1.38 g/ml Dane particle cores purified by equilibrium CsCl density gradient centrifugation and HBcAg particles from HBV infected chimpanzee liver purified in the same way were analyzed by SDS-polyacrylamide gel electrophoresis. Both kinds of particles were found to consistently contain 3 Coomassie blue staining peptides with approximate molecular weights of 19,000, 70,000 and 80,000 daltons (designated P-19, P-70 and P-80 respectively). In addition, the HBcAg particles from infected liver regularly yielded a protein component with molecular weight greater than 200,000 daltons. This component was occasionally present in electrophoresis runs of core peptides from only one of two patients. Its irregular appearance after gel electrophoresis suggests it may have been an aggregate not completely dissociated under the conditions used. The lower density core component consistently contained P-19, P-70, and P-80, and infrequently additional minor peptides of uncertain origin. The irregular occurrence of the minor peptides in varying amounts suggests they were not intrinsic core proteins.

Hepatitis B virus replication in human HepG2 cells mediated by hepatitis B virus recombinant baculovirus

“…In addition, it has been previously reported that unenveloped core particles migrate to the same density. 29 The high concentrations of HBsAg contained in fractions nine to twelve most likely represent HBsAg filaments and spheres which have been reported to migrate to these densities. 31 …”

“…Results from HBsAg and DNA analyses of the gradient suggest that the DS and RC HBV DNA in fractions eight and nine are derived from enveloped Dane particles because HBsAg is present in these fractions and because HBV DNA and HBsAg comigrate at a density which has previously been reported for Dane particles. 29,30 DNA detected in fractions four and five most likely indicates the presence of extracellular core particles lacking envelopes because these fractions are devoid of HBsAg. In addition, it has been previously reported that unenveloped core particles migrate to the same density.…”

Quantitative Detection of Hepatitis B Virus DNA by Real-Time Nucleic Acid Sequence-Based Amplification with Molecular Beacon Detection

“…The 2.2.15 cell line, a well-known HBV-transfected HepG2 cell line, was maintained under conditions described previously (33). After passage through a 40-m-pore-size filter, HBV-positive 2.2.15 cell line culture medium with a high HBV titer (10 9 copies/ml) was subjected to CsCl gradient analysis (16,36). One milliliter of sample was loaded on top of 9 ml of a 20% (wt/wt) CsCl (Boehringer Mannheim, Mannheim, Germany) in phosphate-buffered saline solution.…”

The Biology of Hepadnaviruses

“…wt. components are often seen in liver-derived core preparations (Hruska & Robinson, 1977;Fields et al, 1977). Neurath et al (1978) found that core antigen prepared c, R. HOWARD from sera with or without HBeAg was heterogeneous with respect to isoelectric point; core antigen from HBeAg-positive serum produced two fractions separated by centrifugation in contrast to only one from HBeAg-negative serum.…”