Recruitment of a protein complex containing Tat and cyclin T1 to TAR governs the species specificity of HIV-1 Tat.

Journal Article (Journal Article)

Human cyclin T1 (hCycT1), a major subunit of the essential elongation factor P-TEFb, has been proposed to act as a cofactor for human immunodeficiency virus type 1 (HIV-1) Tat. Here, we show that murine cyclin T1 (mCycT1) binds the activation domain of HIV-1 Tat but, unlike hCycT1, cannot mediate Tat function because it cannot be recruited efficiently to TAR. In fact, overexpression of mCycT1, but not hCycT1, specifically inhibits Tat-TAR function in human cells. This discordant phenotype results from a single amino acid difference between hCycT1 and mCycT1, a tyrosine in place of a cysteine at residue 261. These data indicate that the ability of Tat to recruit CycT1/P-TEFb to TAR determines the species restriction of HIV-1 Tat function in murine cells and therefore demonstrate that this recruitment is a critical function of the Tat protein.

Full Text

Duke Authors

Cited Authors

  • Bieniasz, PD; Grdina, TA; Bogerd, HP; Cullen, BR

Published Date

  • December 1, 1998

Published In

Volume / Issue

  • 17 / 23

Start / End Page

  • 7056 - 7065

PubMed ID

  • 9843510

Pubmed Central ID

  • PMC1171053

International Standard Serial Number (ISSN)

  • 0261-4189

Digital Object Identifier (DOI)

  • 10.1093/emboj/17.23.7056


  • eng

Conference Location

  • England