HIV-1 Tat protein trans-activates transcription in vitro

Robert A. Marciniak, Barbara J. Calnan, Alan D. Frankel, Phillip A. Sharp

Research output: Contribution to journalArticlepeer-review

193 Scopus citations


Tat protein of human immunodeficiency virus 1 is a potent trans-activator of viral gene expression. We show that purified Tat protein stimulates transcription from viral promoters greater than 10-fold in vitro. A Tat protein mutant that does not trans-activate in vivo did not stimulate transcription in vitro. Tat trans-activation required a functional TAR RNA sequence; trans-activation was competed by the addition of in vitro synthesized wild-type TAR RNA but not by mutant TAR RNAs. That Tat protein directly interacts with the TAR RNA during trans-activation in vitro was suggested by competition with Tat peptides. Preliminary evidence suggests the involvement of a cellular factor in recognition of TAR RNA during Tat trans-activation. Analysis of Tat trans-activation in vitro will provide new mechanistic insights into this process and allow a more detailed study of the relationship between Tat protein structure and function.

Original languageEnglish (US)
Pages (from-to)791-802
Number of pages12
Issue number4
StatePublished - Nov 16 1990
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)


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