Characterization of an element within the rat parathyroid hormone parathyroid hormone-related peptide receptor gene promoter that enhances expressionin osteoblastic osteosarcoma 17/2.8 cells

Parathyroid hormone (PTH) and PTH-related peptide (PTHrP) mediate their act ions via a common G-protein-coupled receptor. High levels of PTH/PTHrP rece ptor expression have been detected in many tissues including bone and kidne y. This study has demonstrated specific PTH/PTHrP receptor expression from the U3 promoter in the osteoblastic osteosarcoma ROS 17/2.8 cell line, whic h expresses the endogenous PTH/PTHrP receptor, compared to rat 2 fibroblast s which do not express the endogenous PTH/PTHrP receptor gene. Transient tr ansfection studies revealed cell-specific expression of a construct contain ing 4391 bp of DNA upstream of exon U3 of the PTH/PTHrP receptor gene fused to a luciferase reporter gene. Deletion mapping of the 5' region of U3 rev ealed that a construct containing 206 bp upstream of U3 confers cell-specif ic expression. These data suggest that cell-specific expression in ROS 17/2 .8 involves cell-specific elements within the PTH/PTHrP receptor promoter. (C) 1999 Academic Press.