Identification of Androgen-Regulated Genes in Mouse Kidney by Representational Difference Analysis and Random Arbitrarily Primed Polymerase Chain Reaction

The molecular nature of tissue-specific gene regulation by andro- gens has not been well defined, partly as a result of the variable expression and incomplete regulation of currently available gene models. We have therefore aimed to establish more informative mod- els by identifying alternative genes whose expression is tightly and coordinately regulated by androgens. Female C57BL/6 mice were dosed with dihydrotestosterone- or sham-treated for 8 days, after which kidneys were removed and complementary DNA (cDNA) pre- pared. We then applied the subtractive hybridization techniques of random arbitrarily primed-PCR and PCR-coupled subtractive hy- bridization method of cDNA representational difference analysis to the isolated cDNA. In addition to well characterized androgen-reg- ulated genes (e.g. KAP (kidney androgen-regulated protein)), we dem- onstrate the differential expression of six genes previously not known to be under androgen control. RNA levels of SA, Cytochrome P450 4B1, IL-6ST (interleukin-6 signal transducer), OATP (organic anion transporter), and a newly identified gene, MJAM, were up-regulated by androgen, while 16-a-hydroxylase was decreased. Expression of these transcripts was inhibited in dihydrotestosterone-treated fe- males by flutamide and in males by castration, confirming their de- pendence on androgens. Although all the genes demonstrate tissue- specific regulation by androgen, SA showed both kidney specificity and absolute requirement for androgen for its expression. These newly identified androgen-regulated genes will constitute very useful models for studying the nature of tissue-specific gene regulation by androgens. (Endocrinology 139: 688 - 695, 1998)