P-TEFb kinase is required for HIV Tat transcriptional activation in vivo and in vitro

HSY Mancebo, G Lee, J Flygare… - Genes & …, 1997 - genesdev.cshlp.org
HSY Mancebo, G Lee, J Flygare, J Tomassini, P Luu, Y Zhu, J Peng, C Blau, D Hazuda…
Genes & development, 1997genesdev.cshlp.org
To identify novel inhibitors of transcriptional activation by the HIV Tat protein, we used a
combination of in vitro and in vivo Tat-dependent transcription assays to screen> 100,000
compounds. All compounds identified blocked Tat-dependent stimulation of transcriptional
elongation. Analysis of a panel of structurally diverse inhibitors indicated that their target is
the human homolog of Drosophila positive transcription elongation factor b (P-TEFb). Loss
of Tat transactivation in extracts depleted of the kinase subunit of human P-TEFb, PITALRE …
To identify novel inhibitors of transcriptional activation by the HIV Tat protein, we used a combination of in vitro and in vivo Tat-dependent transcription assays to screen >100,000 compounds. All compounds identified blocked Tat-dependent stimulation of transcriptional elongation. Analysis of a panel of structurally diverse inhibitors indicated that their target is the human homolog ofDrosophila positive transcription elongation factor b (P-TEFb). Loss of Tat transactivation in extracts depleted of the kinase subunit of human P-TEFb, PITALRE, was reversed by addition of partially purified human P-TEFb. Transfection experiments with wild-type or kinase knockout PITALRE demonstrated that P-TEFb is required for Tat function. Our results suggest that P-TEFb represents an attractive target for the development of novel HIV therapeutics.
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