title: Molecular cloning of estrogen receptor alpha of the Nile crocodile.
abstract: Estrogens are essential for normal reproductive activity in female and male vertebrates. In female reptiles, they are essential for ovarian differentiation during a critical developmental stage. To understand the molecular mechanisms of estrogen action in the Nile crocodile (Crocodylus niloticus), we have isolated cDNA encoding the estrogen receptor alpha (ERalpha) from the ovary. Degenerate PCR primers specific to ER were designed and used to amplify Nile crocodile cDNA from the ovary. The full-length Nile crocodile ERalpha cDNA was obtained using 5' and 3' rapid amplification cDNA ends (RACE). The deduced amino acid sequence of the Nile crocodile ERalpha showed high identity to the American alligator ERalpha (98%), caiman ER (98%), lizard ER (82%) and chicken ERalpha (92%), although phylogenetic analysis suggested profound differences in the rate of sequence evolution for vertebrate ER sequences. Expression of ERalpha was observed in the ovary and testis of juvenile Nile crocodiles. These data provide a novel tool allowing future studies examining the regulation and ontogenic expression of ERalpha in crocodiles and expands our knowledge of estrogen receptor evolution.
authors.affiliation: Okazaki Institute for Integrative Bioscience, National Institute for Basic Biology, National Institutes of Natural Sciences, 5-1 Higashiyama, Myodaiji, Okazaki 444-8787, Japan.
authors.forename: Yoshinao
authors.initials: Y
authors.lastname: Katsu
authors.forename: Jan
authors.initials: J
authors.lastname: Myburgh
authors.forename: Satomi
authors.initials: S
authors.lastname: Kohno
authors.forename: Gerry E
authors.initials: GE
authors.lastname: Swan
authors.forename: Louis J
authors.initials: LJ
authors.lastname: Guillette
authors.forename: Taisen
authors.initials: T
authors.lastname: Iguchi
mesh_terms: D000489:Alligators and Crocodiles / Q000235:genetics*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D047628:Estrogen Receptor alpha / Q000235:genetics*; D005260:Female; D006066:Gonads / Q000378:metabolism; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment
chemical_list: D047628:Estrogen Receptor alpha