P-TEFb kinase is required for HIV Tat transcriptional activation in vivo and in vitro.
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, 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.
Mancebo
H S
HS
Tularik, Inc., South San Francisco, California 94080 USA.
Lee
G
G
Flygare
J
J
Tomassini
J
J
Luu
P
P
Zhu
Y
Y
Peng
J
J
Blau
C
C
Hazuda
D
D
Price
D
D
Flores
O
O
D000818:Animals; D019380:Anti-HIV Agents / Q000494:pharmacology*; D001562:Benzimidazoles / Q000494:pharmacology*; D002470:Cell Survival / Q000187:drug effects; D042863:Cyclin-Dependent Kinase 9; D004330:Drosophila; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D015696:Gene Products, tat / Q000037:antagonists & inhibitors / Q000378:metabolism*; D006678:HIV / Q000378:metabolism*; D006367:HeLa Cells; D006801:Humans; D007546:Isoquinolines / Q000494:pharmacology*; D019169:Jurkat Cells; D007700:Kinetics; D015394:Molecular Structure; D042925:Positive Transcriptional Elongation Factor B; D011494:Protein Kinases / Q000172:deficiency / Q000378:metabolism*; D017346:Protein Serine-Threonine Kinases / Q000378:metabolism*; D014158:Transcription, Genetic / Q000187:drug effects; D015533:Transcriptional Activation / Q000187:drug effects; D014162:Transfection; D054322:tat Gene Products, Human Immunodeficiency Virus
D019380:Anti-HIV Agents; D001562:Benzimidazoles; D004791:Enzyme Inhibitors; D015696:Gene Products, tat; D007546:Isoquinolines; D054322:tat Gene Products, Human Immunodeficiency Virus; D011494:Protein Kinases; D042925:Positive Transcriptional Elongation Factor B; D017346:Protein Serine-Threonine Kinases; C467969:CDK9 protein, human; D042863:Cyclin-Dependent Kinase 9