HTLV-I Tax is a zinc-binding protein: role of zinc in Tax structure and function

Virology. 1992 Jun;188(2):754-64. doi: 10.1016/0042-6822(92)90530-3.


We have examined the functional significance of the cysteine- and histidine-rich region (amino acids 22-53) of HTLV-I Tax. A modeling of this region suggests two possible overlapping zinc-finger-like motifs. Using a zinc blotting technique, we show that Tax binds zinc. An N-terminal deletion in Tax that removed this zinc-finger region abolished the ability to bind zinc. Site-directed mutagenesis was used to generate 10 separate mutations so as to discriminate between the two alternative zinc-binding structures. Each Tax mutant was studied for its ability to trans-activate the HTLV-I LTR. Five of the ten mutations inactivated trans-activation. Our results support that one of the two putative zinc fingers is an integral element of Tax structure.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Amino Acid Sequence
  • Cell Nucleus / metabolism
  • Gene Products, tax / chemistry
  • Gene Products, tax / metabolism*
  • Gene Products, tax / ultrastructure
  • Human T-lymphotropic virus 1 / chemistry*
  • Metalloproteins / chemistry
  • Molecular Sequence Data
  • Mutagenesis, Site-Directed
  • Peptide Mapping
  • Protein Conformation
  • Repetitive Sequences, Nucleic Acid
  • Structure-Activity Relationship
  • Transcriptional Activation*
  • Zinc / metabolism*


  • Gene Products, tax
  • Metalloproteins
  • Zinc