Structure and tissue-specific expression of the parathyroid hormone receptor gene

The parathyroid hormone receptor is a member of a vast family of G protein-coupled receptors containing seven transmembrane do-mains. It is the primary target of two ligands, parathyroid hormone (PTH) and PTH related peptide (PTHrP), and as such controls a number of physiological responses. Signaling between PTHrP and the receptor is essential for normal skeletal development in the embryo. In the adult, PTH regulates extracellular fluid calcium levels by interacting with receptors expressed in bone and kidney. The determination of the structure of the mouse parathyroid hormone receptor gene has shown that it is a member of a subfamily of conserved peptide hormone receptors. The gene is expressed in several tissues,and its expression is controlled by at least two promoters. Activity of the upstream promoter is specific to kidney. Our studies provide evidence for the mechanisms which regulate the expression of the parathyroid hormone receptor in multiple tissues in the mouse, and may provide a genetic basis for specific defects in calcium homeostasis seen in humans.