title: Hepatitis B virus DNA-negative dane particles lack core protein but contain a 22-kDa precore protein without C-terminal arginine-rich domain.
abstract: DNA-negative Dane particles have been observed in hepatitis B virus (HBV)-infected sera. The capsids of the empty particles are thought to be composed of core protein but have not been studied in detail. In the present study, the protein composition of the particles was examined using new enzyme immunoassays for the HBV core antigen (HBcAg) and for the HBV precore/core proteins (core-related antigens, HBcrAg). HBcrAg were abundant in fractions slightly less dense than HBcAg and HBV DNA. Three times more Dane-like particles were observed in the HBcrAg-rich fraction than in the HBV DNA-rich fraction by electron microscopy. Western blots and mass spectrometry identified the HBcrAg as a 22-kDa precore protein (p22cr) containing the uncleaved signal peptide and lacking the arginine-rich domain that is involved in binding the RNA pregenome or the DNA genome. In sera from 30 HBV-infected patients, HBcAg represented only a median 10.5% of the precore/core proteins in enveloped particles. These data suggest that most of the Dane particles lack viral DNA and core capsid but contain p22cr. This study provides a model for the formation of the DNA-negative Dane particles. The precore proteins, which lack the arginine-rich nucleotide-binding domain, form viral RNA/DNA-negative capsid-like particles and are enveloped and released as empty particles.
authors.affiliation: Research and Development Division, Advanced Life Science Institute Inc., 2-10-23 Maruyamadai, Wako, Saitama 351-0112, Japan. tkimura@alsi-i.co.jp
authors.forename: Tatsuji
authors.initials: T
authors.lastname: Kimura
authors.forename: Nobuhiko
authors.initials: N
authors.lastname: Ohno
authors.forename: Nobuo
authors.initials: N
authors.lastname: Terada
authors.forename: Akinori
authors.initials: A
authors.lastname: Rokuhara
authors.forename: Akihiro
authors.initials: A
authors.lastname: Matsumoto
authors.forename: Shintaro
authors.initials: S
authors.lastname: Yagi
authors.forename: Eiji
authors.initials: E
authors.lastname: Tanaka
authors.forename: Kendo
authors.initials: K
authors.lastname: Kiyosawa
authors.forename: Shinichi
authors.initials: S
authors.lastname: Ohno
authors.forename: Noboru
authors.initials: N
authors.lastname: Maki
mesh_terms: D000911:Antibodies, Monoclonal / Q000737:chemistry; D000956:Antigens, Viral / Q000737:chemistry; D001120:Arginine / Q000737:chemistry*; D015153:Blotting, Western; D002213:Capsid; D002499:Centrifugation, Density Gradient; D002850:Chromatography, Gel; D003593:Cytoplasm / Q000378:metabolism; D004279:DNA, Viral / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005260:Female; D016679:Genome, Viral; D006509:Hepatitis B / Q000097:blood / Q000821:virology; D006515:Hepatitis B virus / Q000235:genetics*; D006801:Humans; D007124:Immunoenzyme Techniques; D047468:Immunoprecipitation; D008297:Male; D013058:Mass Spectrometry; D008854:Microscopy, Electron; D008957:Models, Genetic; D017434:Protein Structure, Tertiary; D021381:Protein Transport; D011994:Recombinant Proteins / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013395:Sucrose / Q000494:pharmacology; D014758:Viral Core Proteins / Q000737:chemistry
chemical_list: D000911:Antibodies, Monoclonal; D000956:Antigens, Viral; D004279:DNA, Viral; D011994:Recombinant Proteins; D014758:Viral Core Proteins; D013395:Sucrose; D001120:Arginine