The promoter of an androgen dependent gene in the hamster flank organ.

Hamster flank organs are useful for studying androgen-dependent growth of hair follicles and sebaceous glands. A cDNA clone (FAR-17a) was isolated from the hamster flank organ, whose expression was highly sensitive to androgen. The mRNA level of this gene was reduced after castration but reappeared after testosterone treatment. To elucidate the mechanism of expression of this gene regulated by androgen we isolated a genomic clone, from a hamster genomic library, that includes the promoter and upsteam region. The promoter region was used to drive a luciferase reporter gene in Cos 7 cells. This construct was activated five to six times higher over a control plasmid lacking the promoter region. We tested the effects of testosterone by transfection of the reporter plasmid into androgen dependent SC-3 cells. The results showed up to fivefold stimulation after the addition of androgen. The sequence of this promoter region was analyzed and the transcription factor binding sites were predicted. Since no obvious androgen responsive elements were included in the promoter region, we suggest that the stimulation of the reporter construct has to be mediated indirectly by androgen-dependent transcription factor(s).