Cloning and characterization of the murine P2XM receptor gene

We have isolated the murine counterpart of the human P2XM gene (mP2XM), a P 2X purinoceptor that is expressed predominantly in skeletal muscle. The mP2 XM gene, consisting of 12 exons that span 10kb of genomic DNA, encodes a 37 9-amino-acid product with 83% identity to the human homologue. Two potentia l transmembrane domains (M1 and M2) are present in the predicted product, a nd a segment resembling the H5 region of voltage-gated ion channels is comp letely conserved between human and mouse P2XM proteins. Predominant express ion of mP2XM in murine skeletal muscle was confirmed by Northern-blot analy sis, and a low level of expression was detectable in lung tissue, although human lung does not express P2XM.