Characterization of a novel nuclear localization signal in the HTLV-I tax transactivator protein

Virology. 1992 Mar;187(1):316-20. doi: 10.1016/0042-6822(92)90320-o.


The Tax trans-activator protein of the type I human T-cell leukemia virus is expressed predominantly in the nuclei of cells. However, this viral trans-activator is distinguished from most other nuclear proteins by the absence of a short highly basic nuclear localization signal. Previous mutational analyses of the tax gene revealed that many of the missense mutations involving the amino terminus of Tax resulted in a predominantly cytoplasmic pattern of expression. We now report that the amino terminal 48 residues of Tax comprise a functional nuclear localization signal as demonstrated by the ability of this region to retarget expression of a large cytoplasmic protein to the nucleus.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Base Sequence
  • DNA Mutational Analysis
  • Gene Products, tax / chemistry*
  • Gene Products, tax / genetics
  • Gene Products, tax / metabolism
  • Human T-lymphotropic virus 1 / chemistry*
  • Human T-lymphotropic virus 1 / genetics
  • Human T-lymphotropic virus 1 / metabolism
  • Microscopy, Fluorescence
  • Molecular Sequence Data
  • Nuclear Localization Signals
  • Nuclear Proteins / chemistry*
  • Nuclear Proteins / genetics
  • Nuclear Proteins / metabolism
  • Recombinant Fusion Proteins / chemistry
  • Recombinant Fusion Proteins / genetics
  • Recombinant Fusion Proteins / metabolism
  • beta-Galactosidase / genetics
  • beta-Galactosidase / metabolism


  • Gene Products, tax
  • Nuclear Localization Signals
  • Nuclear Proteins
  • Recombinant Fusion Proteins
  • beta-Galactosidase