Structure of the human luteinizing hormone-choriogonadotropin receptor gene: unusual promoter and 5' non-coding regions.

The complete organization of the human luteinizing hormone-choriogonadotropin (LH/CG) receptor (LH/CGR) gene and the structure of 1591 bp of its 5' flanking region have been determined. This gene spans over 70 kbp and contains 11 exons. The first ten exons and part of the last exon encode the extracellular domain of the receptor while the transmembrane and intracellular domains are encoded by the remaining part of the last exon. The gene encodes a 701 amino acids long preprotein, contrary to a previous report of 699 amino acids. Primer extension experiments and polymerase chain reaction (PCR) mapping allowed definition of the transcription initiation site, which is located 1085 bp upstream from the initiation codon. The 5' non-coding region is thus unusually long. The promoter region which is different from the murine LH/CG receptor promoter, contains two putative TATA boxes at positions -34 and -47 and a CAAT box consensus sequence at position -89. A consensus sequence corresponding to a cAMP responsive element is found at position -697. Seven API consensus sequences are also found in the 5' flanking region of the gene. Southern blot experiments demonstrated an informative biallelic polymorphism within the human LH/CG receptor gene locus using BglII endonuclease. The cloning of the human LH/CGR gene and the determination of the organization and structure of its 5' flanking region allow the study of its hormonal, developmental and tissue-specific regulation. Primers and PCR conditions are described for the direct genomic sequencing of all the exons of the gene. This information should facilitate the study of pathological mutations of the receptor.