The gene encoding the ovine gonadotropin-releasing hormone (GnRH) receptor: cloning and initial characterization

We have isolated four lambda clones, which, in their aggregate, contain the entire coding sequence of the ovine gene encoding the gonadotropin-releasing hormone (GnRH) receptor (GnRHR). Like its human and murine counterparts, ovine GnRHR exists as a single-copy gene and is comprised of three exons and two introns. Furthermore, the locations of all exon-intron boundaries are perfectly conserved among the human, ovine and murine genes. The most striking difference among these genes is the location of the transcription start points (tsp) and, thus, the length of 5' untranslated region (UTR). This variation in size of the 5' UTR between the murine, human and ovine genes raises the possibility that different mechanisms have evolved for cell-specific expression of this gene. Isolation of the ovine GnRHR and its associated 5' flanking region is the essential first step in defining the molecular mechanisms underlying cell-specific and hormonal regulation of its expression in ruminants.