Reactivation of the Epstein-Barr virus from viral latency by an S-adenosylhomocysteine hydrolase/14-3-3 zeta/PLA2-dependent pathway

Med Microbiol Immunol. 2006 Dec;195(4):217-23. doi: 10.1007/s00430-006-0022-1. Epub 2006 Jun 21.

Abstract

The S-adenosylhomocysteine hydrolase (SAH) and 14-3-3 zeta/phospholipase A2 (PLA2) are transcriptionally activated in parallel to the induction of the Epstein-Barr virus (EBV) lytic cycle by the ganglioside IV(3)NeuAc-nLcOse(4)Cer. For analysis of the initiation of the viral reactivation, SAH and 14-3-3 zeta/PLA2 were overexpressed. Expression of EA-D, BZLF1, and BHRF1 was increased in response to both, SAH- and 14-3-3 zeta/PLA2 overexpression indicating the initiation of the EBV lytic cycle. Expression of 14-3-3 zeta/PLA2 was shown to be increased in SAH overexpressing cells. Additionally, SAH-triggered initiation of viral reactivation could be inhibited by PLA2-specific inhibitors. The phosphorylation status of protein kinase C (PKC) was shown to be increased in SAH-overexpressing cells. PKC-specific inhibitors arrested SAH-triggered initiation of viral reactivation. Surprisingly, 14-3-3 zeta/PLA2-induced initiation of viral reactivation did not correlate with PKC activation. PKC-specific inhibitors were of no influence. SAH initiated EBV reactivation via the BZLF1-Zp and the BZLF1-Rp promoter, whereas 14-3-3 zeta/PLA2 was connected to the promoter Rp only. Our results suggest two routes of viral reactivation involving SAH, one associated with PKC and BZLF1-Zp, the other associated with 14-3-3 zeta/PLA2 and BZLF1-Rp.

MeSH terms

  • 14-3-3 Proteins / metabolism*
  • Adenosylhomocysteinase / metabolism*
  • Animals
  • Cell Line
  • DNA-Binding Proteins / metabolism
  • DNA-Binding Proteins / pharmacology
  • Gene Expression Regulation, Viral
  • Group IV Phospholipases A2
  • Herpesvirus 4, Human / physiology*
  • Humans
  • Phospholipases A / metabolism*
  • Phospholipases A2
  • Signal Transduction
  • Trans-Activators / metabolism
  • Trans-Activators / pharmacology
  • Viral Proteins / metabolism
  • Viral Proteins / pharmacology
  • Virus Latency / physiology*

Substances

  • 14-3-3 Proteins
  • BZLF1 protein, Herpesvirus 4, Human
  • DNA-Binding Proteins
  • Trans-Activators
  • Viral Proteins
  • Phospholipases A
  • Group IV Phospholipases A2
  • Phospholipases A2
  • Adenosylhomocysteinase