[Identification of prototype foamy virus Bel1 nuclear localization signal and its corresponding importins]

Bing Du Xue Bao. 2014 Jul;30(4):346-52.
[Article in Chinese]

Abstract

Bel1, a transactivator of prototype foamy virus (PFV), plays pivotal roles in the replication of PFV. Previous studies have shown that Bel1 bears a nuclear localization signal (NLS), but its amino acid sequence remains unclear and the corresponding importins have not been identified. In this report, we inserted various fragments of Bel1 into an EGFP-GST fusion protein and investigated their subcellular localization by fluorescence microscopy. We found that the 215PRQKRPR221 fragment could direct nuclear localization, which accords with the consensus sequence K(K/R)X(K/R) of monopartite NLS. Point mutation experiments revealed that K218, R219, and R221 are essential for the nuclear localization of Bel1. The results of the GST-pulldown showed that the Bel1 fragment with residues 215-223, which bears the NLS, interacts with KPNA1, KPNA6, and KPNA7. This result suggests that KPNA1, KPNA6, and KPNA7 maybe involved in Bel1 nuclear translocation.

Publication types

  • English Abstract
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cell Line
  • Cell Nucleus / genetics
  • Cell Nucleus / metabolism
  • Cell Nucleus / virology*
  • Humans
  • Nuclear Localization Signals / genetics*
  • Nuclear Localization Signals / metabolism
  • Protein Binding
  • Protein Transport
  • Retroviridae Infections / genetics
  • Retroviridae Infections / metabolism*
  • Retroviridae Infections / virology
  • Retroviridae Proteins / chemistry
  • Retroviridae Proteins / genetics
  • Retroviridae Proteins / metabolism*
  • Spumavirus / chemistry
  • Spumavirus / genetics*
  • Spumavirus / physiology
  • Trans-Activators / chemistry
  • Trans-Activators / genetics
  • Trans-Activators / metabolism*
  • alpha Karyopherins / genetics
  • alpha Karyopherins / metabolism*

Substances

  • KPNA1 protein, human
  • KPNA6 protein, human
  • KPNA7 protein, human
  • Nuclear Localization Signals
  • Retroviridae Proteins
  • Trans-Activators
  • alpha Karyopherins
  • bel1 protein, Human foamy virus