title: Molecular cloning of anti-Müllerian hormone from the American alligator, Alligator mississippiensis.
abstract: Anti-Müllerian hormone (AMH) plays an important role in male sex differentiation in vertebrates. AMH produced by Sertoli cells of the fetal testis induces regression of the Müllerian duct in mammalian species. In alligators, sexual differentiation is controlled by the temperature during egg incubation, termed temperature-dependent sex determination (TSD). The TSD mechanism inducing sex differentiation is thought to be unique and different from that of genetic sex determination as no gene such as the SRY of mammals has been identified. However, many of the genes associated with gonadal differentiation in mammals also are expressed in the developing gonads of species exhibiting TSD. To clarify the molecular mechanisms associated with gonad formation during the temperature-sensitive period (TSP), we have cloned the full length AMH gene in the alligator, and quantitatively compared mRNA expression patterns in the gonad-adrenal-mesonephros (GAM) complex isolated from alligator embryos incubated at male and female producing temperatures. The deduced amino acid sequence of the alligator AMH cDNA showed high identity (59-53%) to avian AMH genes. AMH mRNA expression was high in the GAM of male alligator embryos at stage 24 (immediately after sex determination) and hatchlings, but suppressed in the GAM of estrogen-exposed hatchlings incubated at the male-producing temperature. In the alligator AMH proximal promoter, a number of transcriptional factors (for SF-1. GATA, WT-1 and SOX9) binding elements were also identified and they exhibit a conserved pattern seen in other species. SOX9 up-regulates transcriptional activity through the amAMH promoter region. These results suggested that AMH and SOX9 play important roles in TSD of the American alligator.
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: Hiroshi
authors.initials: H
authors.lastname: Urushitani
authors.forename: Yoshinao
authors.initials: Y
authors.lastname: Katsu
authors.forename: Shinichi
authors.initials: S
authors.lastname: Miyagawa
authors.forename: Satomi
authors.initials: S
authors.lastname: Kohno
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Ohta
authors.forename: Louis J
authors.initials: LJ
authors.lastname: Guillette
authors.forename: Taisen
authors.initials: T
authors.lastname: Iguchi
mesh_terms: D024506:5' Flanking Region / Q000235:genetics; D000489:Alligators and Crocodiles / Q000235:genetics*; D000569:Americas; D000595:Amino Acid Sequence; D000818:Animals; D054304:Anti-Mullerian Hormone / Q000235:genetics* / Q000378:metabolism; D001483:Base Sequence; D003001:Cloning, Molecular; D005260:Female; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D008297:Male; D008969:Molecular Sequence Data; D010802:Phylogeny; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D055758:SOX9 Transcription Factor / Q000235:genetics / Q000378:metabolism; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid; D014158:Transcription, Genetic
chemical_list: D012333:RNA, Messenger; D055758:SOX9 Transcription Factor; D054304:Anti-Mullerian Hormone