Kaehlcke Katrin, Dorr Alexander, Hetzer-Egger Claudia, Kiermer Veronique, Henklein Peter, Schnoelzer Martina, Loret Erwann, Cole Philip A, Verdin Eric, Ott Melanie
Deutsches Krebsforschungszentrum, D-69120 Heidelberg, Germany.
Mol Cell. 2003 Jul;12(1):167-76. doi: 10.1016/s1097-2765(03)00245-4.
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.
HIV转录激活因子Tat在TAR RNA结合结构域的单个赖氨酸残基处被p300乙酰化。我们已经制备了针对乙酰化形式的Tat（AcTat）的单克隆抗体和多克隆抗体。将抗AcTat抗体显微注射到细胞中可抑制Tat介导的反式激活。同样，p300抑制剂Lys-CoA和针对p300的小干扰RNA（siRNA）可抑制Tat转录活性。全长合成AcTat与TAR RNA结合的亲和力与未乙酰化的Tat相同，但在存在AcTat的情况下，Tat-TAR-细胞周期蛋白T1三元复合物的形成被完全抑制。我们提出，Tat乙酰化可能有助于使Tat辅因子细胞周期蛋白T1从TAR RNA上解离，并有助于将Tat转移到延伸中的RNA聚合酶II上。
