Identification of a human immunodeficiency virus type 1 Tat epitope that is neuroexcitatory and neurotoxic

Avindra Nath, Karen Psooy, Carol Martin, Bodo Knudsen, David S.K. Magnuson, Norman Haughey, Jonathan D. Geiger

Research output: Contribution to journalArticle

268 Scopus citations

Abstract

Tat is an 86- to 104-amino-acid viral protein that activates human immunodeficiency virus type 1 expression, modifies several cellular functions, and causes neurotoxicity. Here, we determined the extent to which peptide fragments of human immunodeficiency virus type 1 BRU Tat1-86 produced neurotoxicity, increased levels of intracellular calcium ([Ca2+](i)), and affected neuronal excitability. Tat31-61 but not Tat48-85 dose dependently increased cytotoxicity and levels of [Ca2+](i) in cultured human fetal brain cells. Similarly, Tat31-61 but not Tat48-85 depolarized rat hippocampal CA1 neurons in slices of rat brain. The neurotoxicity and increases in [Ca2+](i) could be significantly inhibited by non-N-methyl-D-aspartate excitatory amino acid receptor antagonists. Shorter 15-mer peptides which overlapped by 10 amino acids each and which represented the entire sequence of Tat1-86 failed to produce any measurable neurotoxicity. Although it remains to be determined if Tat acts directly on neurons and/or indirectly via glial cells, these findings do suggest that Tat neurotoxicity is conformationally dependent, that the active site resides within the first exon of Tat between residues 31 to 61, and that these effects are mediated at least in part by excitatory amino acid receptors.

Original languageEnglish (US)
Pages (from-to)1475-1480
Number of pages6
JournalJournal of virology
Volume70
Issue number3
DOIs
StatePublished - 1996

ASJC Scopus subject areas

  • Microbiology
  • Immunology
  • Insect Science
  • Virology

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