Characterization of two new members of the formyl peptide receptor gene family from 129S6 mice.

Formyl peptide receptors are G-protein-coupled, seven-transmembrane domain receptors originally identified in leukocytes. Ligands for this class of receptors include the chemotactic peptide fMet-Leu-Phe, lipoxin A(4), serum amyloid A and beta-amyloid peptides. The formyl peptide receptor gene family contains three members in human and six members in mouse. By screening a mouse genomic library, we isolated two novel genes that were provisionally named Fpr-rs6 and Fpr-rs7. They encode putative seven-transmembrane domain proteins of 339 and 338 residues, respectively, and share between them 94% amino acid identity. The predicted amino acid sequences of Fpr-rs6 and Fpr-rs7 are 53-74% identical to other mouse formyl peptide receptors. The transcript of Fpr-rs6 is found in brain, spleen and skeletal muscle, and at high level in testis. The Fpr-rs7 transcript is more widely expressed in heart, liver, lung, spleen, smooth muscle and pancreas. Our data suggest that the expression of Fpr-rs6 and Fpr-rs7 is differentially regulated in mouse despite their high sequence homology.