Acetylation of Tat defines a cyclinT1-independent step in HIV transactivation.
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.
Kaehlcke
Katrin
K
Deutsches Krebsforschungszentrum, D-69120 Heidelberg, Germany.
Dorr
Alexander
A
Hetzer-Egger
Claudia
C
Kiermer
Veronique
V
Henklein
Peter
P
Schnoelzer
Martina
M
Loret
Erwann
E
Cole
Philip A
PA
Verdin
Eric
E
Ott
Melanie
M
D000107:Acetylation; D000123:Acetyltransferases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D000906:Antibodies; D018797:Cell Cycle Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D056906:Cyclin T; D016213:Cyclins / Q000235:genetics*; D015696:Gene Products, tat / Q000037:antagonists & inhibitors / Q000235:genetics* / Q000378:metabolism*; D016325:HIV Long Terminal Repeat / Q000235:genetics; D015497:HIV-1 / Q000235:genetics*; D006367:HeLa Cells; D051548:Histone Acetyltransferases; D006801:Humans; D019169:Jurkat Cells; D046911:Macromolecular Substances; D008958:Models, Molecular; D012319:RNA Polymerase II / Q000096:biosynthesis / Q000235:genetics; D034741:RNA, Small Interfering / Q000494:pharmacology; D014157:Transcription Factors; D015533:Transcriptional Activation / Q000187:drug effects / Q000235:genetics*; D050880:p300-CBP Transcription Factors; D054322:tat Gene Products, Human Immunodeficiency Virus; D000099224:p300-CBP-Associated Factor
D000123:Acetyltransferases; D000906:Antibodies; D018797:Cell Cycle Proteins; D056906:Cyclin T; D016213:Cyclins; D015696:Gene Products, tat; D051548:Histone Acetyltransferases; D046911:Macromolecular Substances; D012319:RNA Polymerase II; D034741:RNA, Small Interfering; D014157:Transcription Factors; D050880:p300-CBP Transcription Factors; D054322:tat Gene Products, Human Immunodeficiency Virus; D000099224:p300-CBP-Associated Factor; C503684:CCNT1 protein, human