Involvement of proteasome in the dynamic assembly of the androgen receptor transcription complex.
We have used the chromatin immunoprecipitation technique to analyze the formation of the androgen receptor (AR) transcription complex onto prostate-specific antigen (PSA) and kallikrein 2 promoters in LNCaP cells. Our results show that loading of holo-AR and recruitment of RNA polymerase II to the promoters occur transiently. The cyclic nature of AR transcription complex assembly is also illustrated by transient association of coactivators GRIP1 and CREB-binding protein and acetylated histone H3 with the PSA promoter. Treatment of cells with the pure antiandrogen bicalutamide also elicits occupancy of the promoter by AR. In contrast to the agonist-liganded AR, bicalutamide-bound receptor is not capable of recruiting polymerase II, GRIP1, or CREB-binding protein, indicating that the conformation of AR bound to anti-androgen is not competent to assemble transcription complexes. Proteasome is involved in the regulation of AR-dependent transcription, as a proteasome inhibitor, MG-132, prevents the release of the receptor from the PSA promoter, and it also blocks the androgen-induced PSA mRNA accumulation. Furthermore, occupancy of the PSA promoter by the 19 S proteasome subcomplex parallels that by AR. Collectively, formation of the AR transcription complex, encompassing AR, polymerase II, and coactivators, on a regulated promoter is a cyclic process involving proteasome function.
Kang
Zhigang
Z
Biomedicum Helsinki, Institute of Biomedicine (Physiology), University of Helsinki and Helsinki University Central Hospital, Finland.
Pirskanen
Asta
A
Jänne
Olli A
OA
Palvimo
Jorma J
JJ
D000726:Androgen Antagonists / Q000494:pharmacology; D000813:Anilides / Q000494:pharmacology; D001483:Base Sequence; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D017931:DNA Primers; D006801:Humans; D007700:Kinetics; D008297:Male; D009097:Multienzyme Complexes / Q000378:metabolism*; D009570:Nitriles; D011401:Promoter Regions, Genetic; D017430:Prostate-Specific Antigen / Q000235:genetics; D011471:Prostatic Neoplasms / Q000201:enzymology / Q000378:metabolism / Q000473:pathology; D046988:Proteasome Endopeptidase Complex; D012319:RNA Polymerase II / Q000378:metabolism; D011944:Receptors, Androgen / Q000235:genetics / Q000378:metabolism*; D014105:Tosyl Compounds; D014158:Transcription, Genetic; D014407:Tumor Cells, Cultured
D000726:Androgen Antagonists; D000813:Anilides; D017931:DNA Primers; D009097:Multienzyme Complexes; D009570:Nitriles; D011944:Receptors, Androgen; D014105:Tosyl Compounds; C053541:bicalutamide; D012319:RNA Polymerase II; D017430:Prostate-Specific Antigen; D003546:Cysteine Endopeptidases; D046988:Proteasome Endopeptidase Complex