HUMAN ESTROGEN-RECEPTOR BETA-GENE STRUCTURE, CHROMOSOMAL LOCALIZATION, AND EXPRESSION PATTERN

The estrogen receptor (ER) is a ligand-activated transcription factor that mediates the effects of the steroid hormone 17 beta-estradiol, in both males and females. Since the isolation and cloning of ER, the co nsensus has been that only one such receptor exists. The finding of a second subtype of ER (ER beta) has caused considerable excitement amon gst endocrinologists. In this article, we present data regarding the g enomic structure and chromosomal localization of the human ER beta gen e, demonstrating that two independent ER genes do exist in the human. Furthermore, we present data regarding the tissue distribution of huma n ER beta, showing that this receptor is expressed in multiple tissues . For instance, ER beta is found in developing spermatids of the testi s, a finding of potential relevance for the ongoing debate on the effe cts of environmental estrogens on sperm counts. In addition, we find E R beta in ovarian granulosa cells, indicating that estrogens also part icipate in the regulation of follicular growth in the human.