1887

Abstract

Rta, an immediate-early protein of Epstein–Barr virus (EBV), is a transcriptional activator that induces lytic gene expression and triggers virus reactivation. Being located predominantly in the nucleus, Rta can exert its transactivation function through either direct DNA binding or certain indirect mechanisms mediated by cellular signalling and other transcriptional factors. This study examined whether the subcellular localization of Rta was critical for the induction of target genes. First, KRKK was identified as a nuclear localization signal (NLS) of Rta. An Rta mutant with the NLS converted to AAAA showed cytoplasmic localization and failed to activate the promoter of BGLF5. Interestingly, ectopic expression of the Rta mutant still disrupted EBV latency in an epithelial cell line. Reporter gene assays revealed that the NLS-mutated Rta retained the ability to activate two lytic promoters, Zp and Rp, at a considerable level. Thus, the cytoplasmic Rta mutant could induce expression of endogenous Zta and Rta, triggering reactivation of EBV.

Loading

Article metrics loading...

/content/journal/jgv/10.1099/vir.0.80556-0
2005-02-01
2024-12-06
Loading full text...

Full text loading...

/deliver/fulltext/jgv/86/2/vir860317.html?itemId=/content/journal/jgv/10.1099/vir.0.80556-0&mimeType=html&fmt=ahah

References

  1. Adamson A. L., Darr D., Holley-Guthrie E., Johnson R. A., Mauser A., Swenson J., Kenney S. 2000; Epstein–Barr virus immediate-early proteins BZLF1 and BRLF1 activate the ATF2 transcription factor by increasing the levels of phosphorylated p38 and c-Jun N-terminal kinases. J Virol 74:1224–1233 [CrossRef]
    [Google Scholar]
  2. Chang L.-K., Liu S.-T. 2000; Activation of the BRLF1 promoter and lytic cycle of Epstein–Barr virus by histone acetylation. Nucleic Acids Res 28:3918–3925 [CrossRef]
    [Google Scholar]
  3. Chang Y., Tung C.-H., Huang Y.-T., Lu J., Chen J.-Y., Tsai C.-H. 1999; Requirement for cell-to-cell contact in Epstein–Barr virus infection of nasopharyngeal carcinoma cells and keratinocytes. J Virol 73:8857–8866
    [Google Scholar]
  4. Chang Y., Chang S.-S., Lee H.-H., Doong S.-L., Takada K., Tsai C.-H. 2004; Inhibition of the Epstein–Barr virus lytic cycle by Zta-targeted RNA interference. J Gen Virol 85:1371–1379 [CrossRef]
    [Google Scholar]
  5. Cox M. A., Leahy J., Hardwick J. M. 1990; An enhancer within the divergent promoter of Epstein–Barr virus responds synergistically to the R and Z transactivators. J Virol 64:313–321
    [Google Scholar]
  6. Darr C. D., Mauser A., Kenney S. 2001; Epstein–Barr virus immediate-early protein BRLF1 induces the lytic form of viral replication through a mechanism involving phosphatidylinositol-3 kinase activation. J Virol 75:6135–6142 [CrossRef]
    [Google Scholar]
  7. Feederle R., Kost M., Baumann M., Janz A., Drouet E., Hammerschmidt W., Delecluse H. J. 2000; The Epstein–Barr virus lytic program is controlled by the co-operative functions of two transactivators. EMBO J 19:3080–3089 [CrossRef]
    [Google Scholar]
  8. Flemington E., Speck S. H. 1990; Autoregulation of Epstein–Barr virus putative lytic switch gene BZLF1. J Virol 64:1227–1232
    [Google Scholar]
  9. Grogan E., Jenson H., Countryman J., Heston L., Gradoville L., Miller G. 1987; Transfection of a rearranged viral DNA fragment, WZhet, stably converts latent Epstein–Barr viral infection to productive infection in lymphoid cells. Proc Natl Acad Sci U S A 84:1332–1336 [CrossRef]
    [Google Scholar]
  10. Gruffat H., Sergeant A. 1994; Characterization of the DNA-binding site repertoire for the Epstein–Barr virus transcription factor R. Nucleic Acids Res 22:1172–1178 [CrossRef]
    [Google Scholar]
  11. Gruffat H., Duran N., Buisson M., Wild F., Buckland R., Sergeant A. 1992; Characterization of an R-binding site mediating the R-induced activation of the Epstein–Barr virus BMLF1 promoter. J Virol 66:46–52
    [Google Scholar]
  12. Hardwick J. M., Tse L., Applegren N., Nicholas J., Veliuona M. A. 1992; The Epstein–Barr virus R transactivator (Rta) contains a complex, potent activation domain with properties different from those of VP16. J Virol 66:5500–5508
    [Google Scholar]
  13. Holley-Guthrie E. A., Quinlivan E. B., Mar E. C., Kenney S. 1990; The Epstein–Barr virus (EBV) BMRF1 promoter for early antigen (EA-D) is regulated by the EBV transactivators, BRLF1 and BZLF1, in a cell-specific manner. J Virol 64:3753–3759
    [Google Scholar]
  14. Hung C.-H., Liu S.-T. 1999; Characterization of the Epstein–Barr virus BALF2 promoter. J Gen Virol 80:2747–2750
    [Google Scholar]
  15. Kalderon D., Roberts B. L., Richardson W. D., Smith A. E. 1984; A short amino acid sequence able to specify nuclear location. Cell 39:499–509 [CrossRef]
    [Google Scholar]
  16. Kenney S., Holley-Guthrie E., Mar E. C., Smith M. 1989; The Epstein–Barr virus BMLF1 promoter contains an enhancer element that is responsive to the BZLF1 and BRLF1 transactivators. J Virol 63:3878–3883
    [Google Scholar]
  17. Kieff E., Rickinson A. B. 2001; Epstein–Barr virus and its replication. In Fields Virology , 4th edn. pp  2511–2573 Edited by Knipe D. M., Howley P. M. Philadelphia: Lippincott Williams & Wilkins;
    [Google Scholar]
  18. Liu P., Speck S. H. 2003; Synergistic autoactivation of the Epstein–Barr virus immediate-early BRLF1 promoter by Rta and Zta. Virology 310:199–206 [CrossRef]
    [Google Scholar]
  19. Liu C., Sista N. D., Pagano J. S. 1996; Activation of the Epstein–Barr virus DNA polymerase promoter by the BRLF1 immediate-early protein is mediated through USF and E2F. J Virol 70:2545–2455
    [Google Scholar]
  20. Manet E., Rigolet A., Gruffat H., Giot J. F., Sergeant A. 1991; Domains of the Epstein–Barr virus (EBV) transcription factor R required for dimerization, DNA binding and activation. Nucleic Acids Res 19:2661–2667 [CrossRef]
    [Google Scholar]
  21. Quinlivan E. B., Holley-Guthrie E. A., Norris M., Gutsch D., Bachenheimer S. L., Kenney S. C. 1993; Direct BRLF1 binding is required for cooperative BZLF1/BRLF1 activation of the Epstein–Barr virus early promoter, BMRF1. Nucleic Acids Res 21:1999–2007 [CrossRef]
    [Google Scholar]
  22. Ragoczy T., Miller G. 2001; Autostimulation of the Epstein–Barr virus BRLF1 promoter is mediated through consensus Sp1 and Sp3 binding sites. J Virol 75:5240–5251 [CrossRef]
    [Google Scholar]
  23. Ragoczy T., Heston L., Miller G. 1998; The Epstein–Barr virus Rta protein activates lytic cycle genes and can disrupt latency in B lymphocytes. J Virol 72:7978–7984
    [Google Scholar]
  24. Sinclair A. J., Brimmell M., Shanahan F., Farrell P. J. 1991; Pathways of activation of the Epstein–Barr virus productive cycle. J Virol 65:2237–2244
    [Google Scholar]
  25. Tsai C.-H., Williams M. V., Glaser R. 1991; Characterization of two monoclonal antibodies to Epstein–Barr virus diffuse early antigen which react to two different epitopes and have different biological function. J Virol Methods 33:47–52
    [Google Scholar]
  26. Tsai C.-H., Liu M.-T., Chen M.-R., Lu J., Yang H.-L., Chen J.-Y., Yang C.-S. 1997; Characterization of monoclonal antibodies to the Zta and DNase proteins of Epstein–Barr virus. J Biomed Sci 4:69–77 [CrossRef]
    [Google Scholar]
  27. Zalani S., Holley-Guthrie E., Kenney S. 1996; Epstein–Barr viral latency is disrupted by the immediate-early BRLF1 protein through a cell-specific mechanism. Proc Natl Acad Sci U S A 93:9194–9199 [CrossRef]
    [Google Scholar]
/content/journal/jgv/10.1099/vir.0.80556-0
Loading
/content/journal/jgv/10.1099/vir.0.80556-0
Loading

Data & Media loading...

This is a required field
Please enter a valid email address
Approval was a Success
Invalid data
An Error Occurred
Approval was partially successful, following selected items could not be processed due to error