Glucocorticoid and androgen receptors have been shown to function through t
he same palindromic glucocorticoid response element (GRE) and yet have diff
erential effects on gene transcription. In this study, we examined the func
tional and structural relationship of the androgen and glucocorticoid recep
tors with the androgen responsive region (ARR) of the probasin (PB) gene co
ntaining two androgen receptor binding sites, ARBS-1 and ARBS-2. Transfecti
on studies indicated that one copy of each cis-acting DNA element was essen
tial for maximal androgen-induced chloramphenicol acetyltransferase (CAT) a
ctivity and that androgen selectivity was maintained when multiple copies o
f the minimal wild type (wt) androgen responsive region containing both ARB
S-1 and ARBS-2 (-244 to -96) were subcloned in front of the thymidine kinas
e promoter. Furthermore, replacing the androgen response region with 1, 2 o
r 3 copies of either ARBS-1 or ARBS-2 restored less than 4% of the biologic
al activity seen with the wt PB ARR. Multiple copies of either ARBS-1 or AR
BS-2 did not result in glucocorticoid-induced CAT gene activity. By compari
son, 1 or 2 copies of the tyrosine aminotransferase (TAT) GRE, as well as t
he mouse mammary tumour virus GRE, were strong inducers of CAT activity in
response to both androgen and glucocorticoid treatment. In addition, band s
hift assays demonstrated that although the synthetic glucocorticoid recepto
r, GR-DNA binding domain (GR-DBD), and the synthetic androgen receptor, AR2
, could interact with the TAT GRE (dissociation constants K-d of 63.9 and 1
4.1 respectively), only AR2 but not GR-DBD binding could be detected on ARB
S-1 and ARBS-2. Our findings provide further evidence that androgen-induced
regulation of gene transcription can occur through androgen-specific DNA b
inding sites that are distinct from the common GRE.