Tat acetylation: A regulatory switch between early and late phases in HIV transcription elongation

Melanie Ott, Alexander Dorr, Claudia Hetzer-Egger, Katrin Kaehlcke, Martina Schnolzer, Peter Henklein, Phil Cole, Ming Ming Zhou, Eric Verdin, Allis, Khochbin

Research output: Contribution to journalArticlepeer-review

42 Scopus citations


The HIV transcriptional activator Tat enhances the processivity of RNA polymerase II by recruiting the CyclinT1/CDK9 complex to the TAR RNA element. In addition, Tat synergizes with the histone acetyltransferase p300 and is acetylated by p300 at a single lysine residue (K50) in the TAR RNA binding domain. We have recently reported that this post-translational modification is necessary for the interaction and transcriptional synergy of Tat with the transcriptional coactivator PCAF. We have further studied the relevance of Tat acetylation during HIV transcription and generated antibodies specific for acetylated Tat (AcTat). Microinjection of anti-AcTat antibodies inhibited Tat-mediated transactivation in cells. Similarly, the specific p300 inhibitor Lys-CoA and short inhibitory RNAs specific for p300 suppressed Tat transcriptional activity. Full-length synthetic AcTat bound to TAR RNA and CyclinT1 with high affinity, but formation of the Tat-TAR-CyclinT1 ternary complex was inhibited when K50 was acetylated. Our data collectively show that Tat acetylation by p300 defines a critical step in Tat transactivation that serves to disrupt the Tat/TAR/CyclinT1 complex and helps in recruiting PCAF to the elongating RNA polymerase II.

Original languageEnglish (US)
Pages (from-to)182-196
Number of pages15
JournalNovartis Foundation Symposium
StatePublished - 2004

ASJC Scopus subject areas

  • General Medicine


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