The presence of a transcription activation function in the hormone-binding domain of androgen receptor is revealed by studies in yeast cells.

To assess the importance of various regions of the androgen receptor (AR) in transcriptional regulation, we have compared its activation functions (AFs) in yeast and mammalian cells. The receptor's amino-terminal region contains a major transcriptional activator (AF-1) in both cell types, whereas AF-2 in the ligand-binding domain (LBD) is very weak in mammalian cells but clearly functional in the yeast. Hormone-binding ability of LBD is mandatory for AF-2 to operate, as illustrated by mutated LBD constructs. The activity of AF-2 in yeast is severely attenuated when the hinge region is attached to LBD, suggesting that the former region modulates AF-2 in vivo, probably by presenting an interface for interacting proteins.