Androgen Receptor Interacts with the Positive Elongation Factor P-TEFb and Enhances the Efficiency of Transcriptional Elongation*
- From the George Whipple Laboratory for Cancer Research, Department of Pathology, Urology, Radiation Oncology, and the Cancer Center, University of Rochester Medical Center, Rochester, New York 14642
Abstract
Androgen receptor (AR) may communicate with the general transcription machinery on the core promoter to exert its function as a transcriptional modulator. Our previous report demonstrated that the AR interacted with transcription factor IIH (TFIIH) under physiological conditions and that overexpression of Cdk-activating kinase, the kinase moiety of TFIIH, enhanced AR-mediated transcription in prostate cancer cells. In an effort to further dissect the mechanisms implicated in AR transactivation, we report here that AR interacts with PITALRE, a kinase subunit of positive elongation factor b (P-TEFb). Cotransfection of the plasmid encoding the mutant PITALRE (mtPITALRE), defective in its RNA polymerase II COOH-terminal domain (CTD)-kinase activity, resulted in preferential inhibition of AR-mediated transactivation. Indeed, AR transactivation in PC-3 cells was preferentially inhibited at the low concentration of 5,6-dicloro-1-β-d-ribofuranosylbenzimidazole (DRB), a CTD kinase inhibitor. These results suggest that CTD phosphorylation may play an important role in AR-mediated transcription. Furthermore, a nuclear run-on transcription assay of the prostate-specific antigen gene, an androgen-inducible gene, showed that transcription efficiency of the distal region of the gene was enhanced upon androgen induction. Taken together, our reports suggest that AR interacts with TFIIH and P-TEFb and enhances the elongation stage of transcription.
Footnotes
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↵* This work was supported by the National Institutes of Health Grants CA55639 and CA71570.The costs of publication of this article were defrayed in part by the payment of page charges. The article must therefore be hereby marked “advertisement” in accordance with 18 U.S.C. Section 1734 solely to indicate this fact.
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↵‡ To whom correspondence should be addressed: University of Rochester Medical Center, 601 Elmwood Ave., Box 626, Rochester, NY 14642. Tel.: 716-273-4500; Fax: 716-756-4133; E-mail: chang@ urmc.rochester.edu.
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Published, JBC Papers in Press, December 21, 2000, DOI 10.1074/jbc.M002285200
- Abbreviations:
- CTD
-
COOH-terminal domain of RNA polymerase II largest subunit
- AR
-
androgen receptor
- DHT
-
dihydrotestosterone
- DRB
-
5,6-dicloro-1-β-d-ribofuranosylbenzimidazole
- NELF
-
negative elongation factor
- PSA
-
prostate-specific antigen
- P-TEFb
-
positive-transcription elongation factor b
- TFIIF and TFIIH
-
transcription factor IIF and IIH, respectively
- FBS
-
fetal bovine serum
- MMTV
-
murine mammary tumor virus
- AR-NDBD
-
AR amino-terminal and DNA-binding domain
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- Received March 17, 2000.
- Revision received December 11, 2000.
- The American Society for Biochemistry and Molecular Biology, Inc.
