REPTILIAN SEX STEROID-RECEPTORS - AMPLIFICATION, SEQUENCE AND EXPRESSION ANALYSIS

Sex steroid hormones secreted by the gonads play a central role in the reproduction of all vertebrates. In addition to direct effects on gam etogenesis, sex steroid hormones are important in sexual development, brain organization, and sexual behavior. The actions of sex steroid ho rmones are mediated primarily by ligand-dependent transcription factor s, or receptors which bind to specific sequences of the DNA and alter the transcription rates of nearby genes. We have used the polymerase c hain reaction to amplify cDNA fragments of the estrogen receptor, prog esterone receptor and androgen receptor from the unisexual whiptail li zard, Cnemidophorus uniparens. The lizard steroid hormone receptors sh are a high degree of sequence homology to the steroid hormone receptor s of other vertebrates. Ribonuclease protection assays demonstrate tha t both estrogen receptor mRNA and progesterone receptor mRNA are incre ased in the oviduct during vitellogenesis and after estrogen treatment . This report demonstrates the utility of the polymerase chain reactio n to generate species specific probes for comparative molecular studie s and provides the first report of cDNA sequences for reptilian steroi d hormone receptors.