Skip to main content
PMC home page
Journal of Virology logoLink to Journal of Virology
. 1994 Jul;68(7):4341–4348. doi: 10.1128/jvi.68.7.4341-4348.1994

Multiple functions of capsid protein phosphorylation in duck hepatitis B virus replication.

M Yu 1, J Summers 1
PMCID: PMC236357  PMID: 8207809

Abstract

We have investigated the role of phosphorylation of the capsid protein of the avian hepadnavirus duck hepatitis B virus in viral replication. We found previously that three serines and one threonine in the C-terminal 24 amino acids of the capsid protein serve as phosphorylation sites and that the pattern of phosphorylation at these sites in intracellular viral capsids is complex. In this study, we present evidence that the phosphorylation state of three of these residues affects distinct steps in viral replication. By substituting these residues with alanine in order to mimic serine, or with aspartic acid in order to mimic phosphoserine, and assaying the effects of these substitutions on various steps in virus replication, we were able to make the following inferences. (i) The presence of phosphoserines at residues 245 and 259 stimulates DNA synthesis within viral nucleocapsids. (ii) The absence of phosphoserine at residue 257 and at residues 257 and 259 stimulates covalently closed circular DNA synthesis and virus production, respectively. (iii) The presence of phosphoserine at position 259 is required for initiation of infection. The results implied that both phosphorylated and nonphosphorylated capsid proteins were necessary for a nucleocapsid particle to carry out all its functions in virus replication, explaining why differential phosphorylation of the capsid protein occurs in hepadnaviruses. Whether these differentially phosphorylated proteins coexist on the same nucleocapsid, or whether the nucleocapsid acquires sequential functions through selective phosphorylation and dephosphorylation, is discussed.

Full text

PDF
4341

Images in this article

4343Image
on p.4343
4344Image
on p.4344
4344Image
on p.4344
4345Image
on p.4345
4345Image
on p.4345
4346Image
on p.4346

Selected References

These references are in PubMed. This may not be the complete list of references from this article.

  1. Condreay L. D., Aldrich C. E., Coates L., Mason W. S., Wu T. T. Efficient duck hepatitis B virus production by an avian liver tumor cell line. J Virol. 1990 Jul;64(7):3249–3258. doi: 10.1128/jvi.64.7.3249-3258.1990. [DOI] [PMC free article] [PubMed] [Google Scholar]
  2. Eckhardt S. G., Milich D. R., McLachlan A. Hepatitis B virus core antigen has two nuclear localization sequences in the arginine-rich carboxyl terminus. J Virol. 1991 Feb;65(2):575–582. doi: 10.1128/jvi.65.2.575-582.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  3. Horwich A. L., Furtak K., Pugh J., Summers J. Synthesis of hepadnavirus particles that contain replication-defective duck hepatitis B virus genomes in cultured HuH7 cells. J Virol. 1990 Feb;64(2):642–650. doi: 10.1128/jvi.64.2.642-650.1990. [DOI] [PMC free article] [PubMed] [Google Scholar]
  4. Kawaguchi T., Nomura K., Hirayama Y., Kitagawa T. Establishment and characterization of a chicken hepatocellular carcinoma cell line, LMH. Cancer Res. 1987 Aug 15;47(16):4460–4464. [PubMed] [Google Scholar]
  5. Kunkel T. A., Roberts J. D., Zakour R. A. Rapid and efficient site-specific mutagenesis without phenotypic selection. Methods Enzymol. 1987;154:367–382. doi: 10.1016/0076-6879(87)54085-x. [DOI] [PubMed] [Google Scholar]
  6. Mandart E., Kay A., Galibert F. Nucleotide sequence of a cloned duck hepatitis B virus genome: comparison with woodchuck and human hepatitis B virus sequences. J Virol. 1984 Mar;49(3):782–792. doi: 10.1128/jvi.49.3.782-792.1984. [DOI] [PMC free article] [PubMed] [Google Scholar]
  7. Mason W. S., Aldrich C., Summers J., Taylor J. M. Asymmetric replication of duck hepatitis B virus DNA in liver cells: Free minus-strand DNA. Proc Natl Acad Sci U S A. 1982 Jul;79(13):3997–4001. doi: 10.1073/pnas.79.13.3997. [DOI] [PMC free article] [PubMed] [Google Scholar]
  8. Mason W. S., Halpern M. S., England J. M., Seal G., Egan J., Coates L., Aldrich C., Summers J. Experimental transmission of duck hepatitis B virus. Virology. 1983 Dec;131(2):375–384. doi: 10.1016/0042-6822(83)90505-6. [DOI] [PubMed] [Google Scholar]
  9. Pugh J. C., Summers J. W. Infection and uptake of duck hepatitis B virus by duck hepatocytes maintained in the presence of dimethyl sulfoxide. Virology. 1989 Oct;172(2):564–572. doi: 10.1016/0042-6822(89)90199-2. [DOI] [PubMed] [Google Scholar]
  10. Pugh J., Zweidler A., Summers J. Characterization of the major duck hepatitis B virus core particle protein. J Virol. 1989 Mar;63(3):1371–1376. doi: 10.1128/jvi.63.3.1371-1376.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  11. Schlicht H. J., Bartenschlager R., Schaller H. The duck hepatitis B virus core protein contains a highly phosphorylated C terminus that is essential for replication but not for RNA packaging. J Virol. 1989 Jul;63(7):2995–3000. doi: 10.1128/jvi.63.7.2995-3000.1989. [DOI] [PMC free article] [PubMed] [Google Scholar]
  12. Summers J., Mason W. S. Replication of the genome of a hepatitis B--like virus by reverse transcription of an RNA intermediate. Cell. 1982 Jun;29(2):403–415. doi: 10.1016/0092-8674(82)90157-x. [DOI] [PubMed] [Google Scholar]
  13. Summers J., Smith P. M., Horwich A. L. Hepadnavirus envelope proteins regulate covalently closed circular DNA amplification. J Virol. 1990 Jun;64(6):2819–2824. doi: 10.1128/jvi.64.6.2819-2824.1990. [DOI] [PMC free article] [PubMed] [Google Scholar]
  14. Summers J., Smith P. M., Huang M. J., Yu M. S. Morphogenetic and regulatory effects of mutations in the envelope proteins of an avian hepadnavirus. J Virol. 1991 Mar;65(3):1310–1317. doi: 10.1128/jvi.65.3.1310-1317.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  15. Tuttleman J. S., Pourcel C., Summers J. Formation of the pool of covalently closed circular viral DNA in hepadnavirus-infected cells. Cell. 1986 Nov 7;47(3):451–460. doi: 10.1016/0092-8674(86)90602-1. [DOI] [PubMed] [Google Scholar]
  16. Tuttleman J. S., Pugh J. C., Summers J. W. In vitro experimental infection of primary duck hepatocyte cultures with duck hepatitis B virus. J Virol. 1986 Apr;58(1):17–25. doi: 10.1128/jvi.58.1.17-25.1986. [DOI] [PMC free article] [PubMed] [Google Scholar]
  17. Wu T. T., Coates L., Aldrich C. E., Summers J., Mason W. S. In hepatocytes infected with duck hepatitis B virus, the template for viral RNA synthesis is amplified by an intracellular pathway. Virology. 1990 Mar;175(1):255–261. doi: 10.1016/0042-6822(90)90206-7. [DOI] [PubMed] [Google Scholar]
  18. Yeh C. T., Wong S. W., Fung Y. K., Ou J. H. Cell cycle regulation of nuclear localization of hepatitis B virus core protein. Proc Natl Acad Sci U S A. 1993 Jul 15;90(14):6459–6463. doi: 10.1073/pnas.90.14.6459. [DOI] [PMC free article] [PubMed] [Google Scholar]
  19. Yu M., Summers J. A domain of the hepadnavirus capsid protein is specifically required for DNA maturation and virus assembly. J Virol. 1991 May;65(5):2511–2517. doi: 10.1128/jvi.65.5.2511-2517.1991. [DOI] [PMC free article] [PubMed] [Google Scholar]
  20. Yu M., Summers J. Phosphorylation of the duck hepatitis B virus capsid protein associated with conformational changes in the C terminus. J Virol. 1994 May;68(5):2965–2969. doi: 10.1128/jvi.68.5.2965-2969.1994. [DOI] [PMC free article] [PubMed] [Google Scholar]

Articles from Journal of Virology are provided here courtesy of American Society for Microbiology (ASM)

RESOURCES