Distinct regions of cyclinT1 are required for binding to CDK9 and for recruitment to the HIV-1 Tat/TAR complex.
Tat-mediated activation of the HIV-1 promoter activity requires Tat-dependent recruitment of the cyclinT1/CDK9 complex (P-TEFb) to the transacting element (TAR) RNA. Tat interaction with the cyclinT1, the regulatory partner of CDK9, results in a specific recruitment of the heterodimer CycT1/CDK9 complex to TAR, whereby it promotes transcription elongation of the HIV-1 LTR-mediated transcription. Using the yeast two-hybrid protein interaction assay we analyzed the binding between cyclinT1 and CDK9. Moreover, using a modified three-hybrid yeast interaction system, we analyzed the recruitment of CycT1 to the Tat/TAR complex. The data presented here demonstrated that distinct domains of cyclinT1 interact with CDK9 and Tat/TAR in vivo. These findings will be instrumental for the designing of proper dominant-negative P-TEFb components capable to interfere with Tat function. J. Cell. Biochem. Suppl. 36: 247-253, 2001.
Fraldi
A
A
Department of Genetics, Molecular and General Biology, University Federico II, Via Mezzocannone 8, 80134 Naples, Italy.
Licciardo
P
P
Majello
B
B
Giordano
A
A
Lania
L
L
D001665:Binding Sites; D042863:Cyclin-Dependent Kinase 9; D018844:Cyclin-Dependent Kinases / Q000378:metabolism*; D016213:Cyclins / Q000378:metabolism*; D015696:Gene Products, tat / Q000378:metabolism*; D016325:HIV Long Terminal Repeat; D015497:HIV-1 / Q000378:metabolism*; D020798:Two-Hybrid System Techniques; D015003:Yeasts; D054322:tat Gene Products, Human Immunodeficiency Virus
D016213:Cyclins; D015696:Gene Products, tat; D054322:tat Gene Products, Human Immunodeficiency Virus; D042863:Cyclin-Dependent Kinase 9; D018844:Cyclin-Dependent Kinases