A NOVEL HUMAN LUTEINIZING-HORMONE RECEPTOR GENE

A novel human luteinizing hormone receptor (LHR) gene was isolated fro m a human placental genomic library. This gene (Gene II) differs from that previously isolated from a lymphocyte library (Gene I) by several base changes in the 5' flanking region and the deletion of 6 nucleoti des in the coding region (+55 to +60). The sequence of the exon 1 codi ng region of gene II conforms to the sequence of the human ovarian LHR cDNA. Furthermore, primer extension and reporter gene analyses indica te that both the Gene II promoter and the human ovarian LHR mRNA trans criptional start sites are located within the -176 bp TATA-less 5' fla nking domain. Additional upstream transcriptional start sites (>-176 b p) were identified in human testicular mRNA and the human choriocarcin oma JAR cell. Restriction enzyme analysis verifies that both LHR genes are present in the human genome, and gene dosing reveals four copies of the human LHR in contrast to a single copy in the rat genome. Chrom osomal mapping localizes all copies of the human LHR to the chromosome 2p16-21 loci. These studies suggest that tissue-specific LHR promoter utilization and LHR gene expression may be correlated with gene diver sity.