The second largest subunit of RNA polymerase II interacts with and enhances transactivation of androgen receptor

AR may communicate with the general transcription machinery on the core promoter to exert its function as a transcriptional modulator. Our previous reports demonstrated that AR interacted with TFIIH and positive transcription elongation factor b (P-TEFb), and that phosphorylation of the carboxy-terminal domain in the largest subunit of RNA polymerase II might play important roles in AR-mediated transcription. These results suggest that AR may modulate gene expression by enhancing the efficiency of transcriptional elongation. Here we further demonstrate that co-expression of the second largest subunit of RNA polymerase II (RPB2) enhances AR transactivation. However, co-expression of the other subunits of RNA polymerase II or TFIIB did not show preferential enhancement of AR-mediated transcription. Furthermore, co-transfection of RPB2 with ER showed little effect on enhancement of ER transactivation. Together, AR may be able to interact with TFIIH, P-TEFb, and RPB2 to enhance transcription from AR target genes, such as prostate specific antigen that may play important roles in the prostate cancer progression.