Translation of hepatitis B virus (HBV) surface proteins from the HBV pregenome and precore RNAs in Semliki Forest virus-driven expression.
Hepatitis B virus (HBV) pregenome RNA (pgRNA) serves as a translation template for the HBV core (HBc) protein and viral polymerase (Pol). HBV precore RNA (pcRNA) directs the synthesis of the precore (preC) protein, a precursor of the hepatitis B e antigen (HBeAg). pgRNA and pcRNA were expressed in the Semliki Forest virus (SFV) expression system. Besides the HBc and preC proteins, there was revealed the synthesis of all three forms of HBV surface (HBs) proteins: long (LHBs), middle (MHBs) and short (SHBs), the start codons of which are located more than 1000 nt downstream of the HBc and preC start codons. Moreover, other HBV templates, such as 3'-truncated pgRNA lacking 3' direct repeat and Pol mRNA, both carrying internally the HBs sequences, provided the synthesis of three HBs protein forms in the SFV-driven expression system. Maximal production of the HBs was provided by Pol mRNA, while HBc- and preC-producing templates showed relatively low internal translation of the HBs. These data allow the proposal of a ribosome leaky scanning model of internal translation initiation for HBs proteins. The putative functional role of such exceptional synthesis of the HBs proteins from the pgRNA and pcRNA templates in the natural HBV infection process needs further evaluation.
Department of Protein Engineering, Biomedical Research and Study Centre, University of Latvia, Ratsupites Str., 1, LV-1067 Riga, Latvia.
Anna
A
Zajakina
Department of Protein Engineering, Biomedical Research and Study Centre, University of Latvia, Ratsupites Str., 1, LV-1067 Riga, Latvia.
Tatyana
T
Kozlovska
Department of Protein Engineering, Biomedical Research and Study Centre, University of Latvia, Ratsupites Str., 1, LV-1067 Riga, Latvia.
Ruta
R
Bruvere
Department of Protein Engineering, Biomedical Research and Study Centre, University of Latvia, Ratsupites Str., 1, LV-1067 Riga, Latvia.
Jekaterina
J
Aleksejeva
Department of Protein Engineering, Biomedical Research and Study Centre, University of Latvia, Ratsupites Str., 1, LV-1067 Riga, Latvia.
Paul
P
Pumpens
Department of Biosciences at Novum, Karolinska Institute, S-141 57 Huddinge, Sweden.
Henrik
H
Garoff
D000818:Animals; D002460:Cell Line; D003001:Cloning, Molecular; D004259:DNA-Directed DNA Polymerase / Q000096:biosynthesis / Q000235:genetics; D015870:Gene Expression; D006512:Hepatitis B Core Antigens / Q000096:biosynthesis; D006514:Hepatitis B Surface Antigens / Q000032:analysis / Q000096:biosynthesis / Q000235:genetics*; D006513:Hepatitis B e Antigens / Q000096:biosynthesis; D006515:Hepatitis B virus / Q000235:genetics*; D007150:Immunohistochemistry; D014176:Protein Biosynthesis; D011498:Protein Precursors / Q000096:biosynthesis / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000096:biosynthesis / Q000378:metabolism; D012367:RNA, Viral / Q000096:biosynthesis / Q000378:metabolism; D012672:Semliki forest virus / Q000235:genetics / Q000378:metabolism*; D013698:Templates, Genetic; D014759:Viral Envelope Proteins / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics; D014779:Virus Replication
D006512:Hepatitis B Core Antigens; D006514:Hepatitis B Surface Antigens; D006513:Hepatitis B e Antigens; D011498:Protein Precursors; D012333:RNA, Messenger; D012367:RNA, Viral; D014759:Viral Envelope Proteins; D004259:DNA-Directed DNA Polymerase