In vitro regulation of reporter gene transcription by the androgen receptor AF1 domain

• Published in: Biochemical Society transactions Vol. 32; no. Pt 6; p. 1103
• Main Authors: Choudhry, M A, McEwan, I J
• Format: Journal Article
• Language: English
• Published: England 01.12.2004
• Subjects: Base Sequence; Binding Sites; Cell-Free System; Gene Expression Regulation; Humans; Molecular Sequence Data; Receptors, Androgen - chemistry; Receptors, Androgen - physiology; Transcription Factors, TFII - metabolism; Transcription, Genetic
• ISSN: 0300-5127
• DOI: 10.1042/BST0321103

The androgen receptor (AR) is a ligand-activated transcription factor that regulates gene expression in response to the steroids testosterone and dihydrotestosterone. AR-dependent gene expression is likely to play an important role in a number of receptor-associated disorders, such as prostate cancer, spinal bulbar muscular atrophy, male type baldness and hirsutism. The AR contains two transactivation domains, termed AF1 (activation function 1) located in the N-terminus and AF2 (activation function 2) in the C-terminal ligand-binding domain. AF2 exhibits weak transcriptional activity, whereas AF1 is a strong regulator of transcription. Transcriptional regulation by AF1 is thought to be modulated by a number of proteins that interact with this region, and by post-translational modifications. Our focus is on the N-terminal-interacting proteins and their regulation of transcription via interaction with the receptor. To better understand the mechanism of AR-AF1 action, we have reconstituted AR activity in HeLa nuclear extracts using a unique dual reporter gene assay. Multiple LexA-binding sites in the promoter allow transcription to be driven by a recombinant AR-AF1-Lex fusion protein. The findings from initial experiments suggest an increase in transcription initiation and elongation rates by AR-AF1-Lex. The role of protein-protein interactions involving co-activators and basal transcription factors and AR-AF1 activity are discussed.