Epstein-Barr virus noncoding RNAs are confined to the nucleus, whereas their partner, the human La protein, undergoes nucleocytoplasmic shuttling

J Cell Biol. 2006 May 8;173(3):319-25. doi: 10.1083/jcb.200601026.

Abstract

The Epstein-Barr virus (EBV) noncoding RNAs, EBV-encoded RNA 1 (EBER1) and EBER2, are the most abundant viral transcripts in all types of latently infected human B cells, but their function remains unknown. We carried out heterokaryon assays using cells that endogenously produce EBERs to address their trafficking, as well as that of the La protein, because EBERs are quantitatively bound by La in vivo. Both in this assay and in oocyte microinjection assays, EBERs are confined to the nucleus, suggesting that their contribution to viral latency is purely nuclear. EBER1 does not bind exportin 5; therefore, it is unlikely to act by interfering with microRNA biogenesis. In contrast, La, which is a nuclear phosphoprotein, undergoes nucleocytoplasmic shuttling independent of the nuclear export protein Crm1. To ensure that small RNA shuttling can be detected in cells that are negative for EBER shuttling, we demonstrate the shuttling of U1 small nuclear RNA.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Active Transport, Cell Nucleus / drug effects
  • Animals
  • Antibiotics, Antineoplastic / pharmacology
  • Autoantigens / metabolism*
  • Cell Line
  • Cell Line, Tumor
  • Cell Nucleus / drug effects
  • Cell Nucleus / metabolism*
  • Dactinomycin / pharmacology
  • Fatty Acids, Unsaturated / pharmacology
  • Female
  • HeLa Cells
  • Herpesvirus 4, Human / genetics*
  • Humans
  • Karyopherins / genetics
  • Karyopherins / metabolism
  • Mice
  • NIH 3T3 Cells
  • Oocytes / metabolism
  • Protein Binding
  • RNA Transport / drug effects
  • RNA, Untranslated / genetics
  • RNA, Untranslated / metabolism*
  • RNA, Viral / genetics
  • RNA, Viral / metabolism*
  • Ribonucleoproteins / metabolism*
  • SS-B Antigen
  • Xenopus laevis

Substances

  • Antibiotics, Antineoplastic
  • Autoantigens
  • Epstein-Barr virus encoded RNA 1
  • Epstein-Barr virus encoded RNA 2
  • Fatty Acids, Unsaturated
  • Karyopherins
  • RNA, Untranslated
  • RNA, Viral
  • Ribonucleoproteins
  • XPO5 protein, human
  • Dactinomycin
  • leptomycin B