Distinct regions of cyclinT1 are required for binding to CDK9 and for recruitment to the HIV-1 Tat/TAR complex

✍ Scribed by Alessandro Fraldi; Paolo Licciardo; Barbara Majello; Antonio Giordano; Luigi Lania

• Book ID: 102303493
• Publisher: John Wiley and Sons
• Year: 2001
• Tongue: English
• Weight: 164 KB
• Volume: 81
• Category: Article
• ISSN: 0730-2312
• DOI: 10.1002/jcb.1149

✦ Synopsis

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 speci®c 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 modi®ed 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 ®ndings will be instrumental for the designing of proper dominant-negative P-TEFb components capable to interfere with Tat function. J.