title: Highly heterologous region in the N-terminal extracellular domain of reptilian follitropin receptors.
abstract: The primary structure of the N-terminal extracellular region of the follitropin receptor (FSH-R), which is thought to be responsible for hormone binding specificity, was determined in three reptilian species (tortoise, gecko, and lizard). Remarkably low sequence homologies were detected in the C-terminal part of the extracellular domain. This region was estimated to be a part of exon 10, which is the last exon of the FSH-R gene. In this region, not only were low homologies detected among the three reptilian species, but also specific deletions and/or insertions were found. In particular, large deletions were detected in squamate (gecko and lizard) FSH-Rs. Phylogenetic analysis indicated that these large deletions occurred recently, i.e., after the Triassic period. In another region characterized, sequence homologies were high, with tortoise-rat homology 78.4%, gecko-rat 64.7%, and lizard-rat 69.1%. In this highly conserved region, however, some reptile-specific alterations were detected, such as the loss of a cysteine residue in putative exon 7 and the existence of potential N-linked glycosylation sites in putative exon 9.
authors.affiliation: Department of Biological Sciences, Graduate School of Science, University of Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Akazome
authors.forename: O
authors.initials: O
authors.lastname: Ogasawara
authors.forename: M K
authors.initials: MK
authors.lastname: Park
authors.forename: T
authors.initials: T
authors.lastname: Mori
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D005091:Exons; D017353:Gene Deletion; D006031:Glycosylation; D008116:Lizards; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D016133:Polymerase Chain Reaction; D011962:Receptors, FSH / Q000737:chemistry* / Q000235:genetics; D017385:Sequence Homology; D014426:Turtles
chemical_list: D011962:Receptors, FSH