title: Inhibition of secretion of hepatitis B surface antigen by a related presurface polypeptide.
abstract: The presurface (preS) proteins of hepatitis B virus are structural components of the viral envelope that may play important roles in virion assembly and infectivity. They are specified by a large open reading frame that includes the coding region for the major surface (S) protein in its 3' half. Translation of the preS proteins initiates upstream from the S region, giving rise to proteins that are composed of the S domain and an additional 163 (preS1) or 55 (preS2) amino acids. Little is known about the biosynthesis and assembly of these proteins. The expression of the S and preS1 proteins was examined by transfecting cultured mammalian cells with viral DNA and injecting synthetic messenger RNA's into Xenopus oocytes. In contrast to the proteins encoded by the S region, the preS1 proteins are not detectably secreted into the culture medium. Furthermore, when the S and preS1 proteins are synthesized together, secretion of the S proteins is specifically and strongly inhibited. The results suggest a unique molecular interaction during secretion of the S and preS proteins that may be important for virus assembly.
mesh_terms: D000818:Animals; D004279:DNA, Viral / Q000008:administration & dosage; D006514:Hepatitis B Surface Antigens / Q000235:genetics / Q000378:metabolism* / Q000494:pharmacology*; D006515:Hepatitis B virus / Q000235:genetics / Q000472:pathogenicity; D014176:Protein Biosynthesis; D011498:Protein Precursors / Q000235:genetics / Q000494:pharmacology*; D014771:Virion / Q000472:pathogenicity; D014779:Virus Replication; D014981:Xenopus
chemical_list: D004279:DNA, Viral; D006514:Hepatitis B Surface Antigens; D011498:Protein Precursors; C050806:presurface protein 1, hepatitis B surface antigen; C050807:presurface protein 2, hepatitis B surface antigen