SEQUENCE AND ORGANIZATION OF THE HUMAN N-FORMYL PEPTIDE RECEPTOR-ENCODING GENE

The human FPR1 gene encodes the N-formyl peptide receptor, a G protein -coupled receptor (GPCR) that mediates the activation of mature myeloi d cells by bacterial N-formyl oligopeptides. To investigate the molecu lar basis for myeloid-specific production of this receptor, we have cl oned and sequenced FPR1. The gene is organized into three exons and tw o introns that span 6 kb. The coding block lacks introns. Yet, the tra nscription start point (tsp) is separated from the start codon by 4902 bp consisting of three exons and two large introns. Two mRNAs are pro duced by alternative splicing of exon 2 in HL-60 neutrophils and norma l blood monocytes. The region 5' to the tsp contains three pyrimidine- rich segments, a feature that has been observed in other myeloid-speci fic genes. One complete Alu repeat is found in each intron and in the 3'-flanking region 317 bp downstream of the polyadenylation signal. Th us, FPR1 is a small myeloid-specific gene that is expressed as two alt ernatively spliced mRNAs encoding the same protein.