Cloning of P2Y6 cDNAs and identification of a pseudogene: comparison of P2Y receptor subtype expression in bone and brain tissues.

Cellular responses to ATP/UTP and analogs are mediated by G-protein coupled P2Y receptors and have been proposed to play a role in the regulation of bone metabolism. Using a degenerate PCR approach on MG-63 cell cDNA we found PCR fragments coding for human P2Y1 and a new receptor, P2Y6. cDNA cloning of the P2Y6 receptor identified three of cDNA isoforms. Two contained the same contiguous ORFs but differed in their 5 UTRs and may therefore originate by alternative splicing whereas the third represents a pseudogene. Analysis of P2Y receptor subtype expression in human bone and the osteoblastic cell lines OHS-4 and MG-63 by RT-PCR showed that all known human P2Y receptor subtypes (P2Y1, P2Y2, P2Y4, P2Y6, and P2Y7) were expressed. In contrast, analysis of brain-derived cell lines suggests that a selective expression of P2Y receptor subtypes occurs in brain tissue.