Identification and Characterization of a Structural Protein of Hepatitis B Virus: A Polymerase and Surface Fusion Protein Encoded by a Spliced RNA
| Autor: | Chungming Chang, King-Song Jeng, Szecheng J. Lo, Cheng-Po Hu, Huey-Lan Huang, Chiu-Ho Tsai |
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| Rok vydání: | 2000 |
| Předmět: |
Hepatitis B virus
Vesicle-associated membrane protein 8 Glycosylation RNA Splicing LRP1B Gene Products pol Cell Line Retinoblastoma-like protein 1 Epitopes Open Reading Frames Virology Protein A/G SNAP23 HSPA2 Aspartic Acid Endopeptidases Humans Glycoproteins Viral Structural Proteins NAB2 Hepatitis B Surface Antigens biology Reverse Transcriptase Polymerase Chain Reaction Precipitin Tests Fusion protein Molecular biology Molecular Weight biology.protein Electrophoresis Polyacrylamide Gel Viral Fusion Proteins |
| Zdroj: | Virology. 275:398-410 |
| ISSN: | 0042-6822 |
| DOI: | 10.1006/viro.2000.0478 |
| Popis: | The hepatitis B virus (HBV) genome is known to contain four conserved and overlapped open reading frames (ORFs) encoding the viral core, polymerase (P), surface (S), and X proteins. Whether HBV encodes other proteins has long been a major interest in the field. Using 32P-labeling of an introduced protein kinase A site attached to the N- or C-terminus of the HBV polymerase gene, a 43-kDa P–S fusion protein was detected in cell lysate, secreted virions, and 22-nm subviral particles. Immunobiochemical studies showed that the 43-kDa protein contains the epitopes of the N-terminus of polymerase and most parts of the surface proteins. This 43-kDa protein was shown to be a glycoprotein, similar to the surface protein. RT-PCR and sequence analyses identified a spliced mRNA which was derived from pregenomic RNA with a deletion of 454 nucleotides (nt) from nt 2447 to 2902. This splice event creates a P–S fusion ORF. This finding is consistent with the result obtained from an immunobiochemical study. Mutations at the splice donor or acceptor site on the HBV genome abrogated the production of the 43-kDa protein. These mutants had no effect on viral replication in transfected HuH-7 cells. However, this P–S fusion protein is able to substitute for the LS protein in virion maturation. On the basis of these results, we conclude that the 43-kDa protein is a polymerase-surface fusion protein encoded by a spliced RNA. Similar to the LS protein, the 43-kDa P–S fusion protein is a structural protein of HBV and might play a role in the HBV life cycle. |
| Databáze: | OpenAIRE |
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