Acetylation of Tat defines a CyclinT1-independent step in HIV transactivation

Katrin Kaehlcke, Alexander Dorr, Claudia Hetzer-Egger, Veronique Kiermer, Peter Henklein, Martina Schnoelzer, Erwann Loret, Philip A. Cole, Eric Verdin, Melanie Ott

Research output: Contribution to journalArticlepeer-review

97 Scopus citations


The HIV transcriptional activator Tat is acetylated by p300 at a single lysine residue in the TAR RNA binding domain. We have generated monoclonal and polyclonal antibodies specific for the acetylated form of Tat (AcTat). Microinjection of anti-AcTat antibodies inhibited Tat-mediated transactivation in cells. Similarly, the p300 inhibitor Lys-CoA and siRNA specific for p300 suppressed Tat transcriptional activity. Full-length synthetic AcTat bound to TAR RNA with the same affinity as unacetylated Tat, but formation of a Tat-TAR-CyclinT1 ternary complex was completely inhibited in the presence of AcTat. We propose that Tat acetylation may help in dissociating the Tat cofactor CyclinT1 from TAR RNA and serve to transfer Tat onto the elongating RNA polymerase II.

Original languageEnglish (US)
Pages (from-to)167-176
Number of pages10
JournalMolecular cell
Issue number1
StatePublished - Jul 1 2003
Externally publishedYes

ASJC Scopus subject areas

  • Molecular Biology
  • Cell Biology


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