title: Sequence divergence and expression of a transformer gene in the branchiopod crustacean, Daphnia magna.
abstract: Environmental decline triggers a switch in reproductive strategy of Daphnia magna from asexual to sexual reproduction; however, the molecular basis of such environmental sex determination remains largely unknown. In insects most closely related to branchiopod crustaceans, orthologs of the Drosophila transformer gene such as dipteran transformer (tra), honeybee feminizer (fem) and complementary sex determiner (csd) function as sex determining factors. Therefore, we cloned a D. magna transformer gene (dmagtra) and analyzed its expression. The predicted amino acid sequence has 380 amino acids including an arginine-serine-rich region, which is characteristic of insect orthologs of Tra. Residues 180 to 205 are highly conserved with known Tra orthologs. The domain organization of DmagTra is distinct from known Tra orthologs; moreover, dmagtra does not display any detectable sexual dimorphic differences in expression or splicing patterns. We infer from these results that dmagtra may not be responsible for sex determination in D. magna.
authors.affiliation: Okazaki Institute for Integrative Bioscience, National Institute for Basic Biology, National Institutes of Natural Sciences, and Department of Basic Biology, Faculty of Life Science, Graduate University for Advanced Studies, 5-1 Higashiyama, Myodaiji, Okazaki, Aichi 444-8787, Japan.
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Kato
authors.forename: Kaoru
authors.initials: K
authors.lastname: Kobayashi
authors.forename: Shigeto
authors.initials: S
authors.lastname: Oda
authors.forename: Norihisa
authors.initials: N
authors.lastname: Tatarazako
authors.forename: Hajime
authors.initials: H
authors.lastname: Watanabe
authors.forename: Taisen
authors.initials: T
authors.lastname: Iguchi
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D003621:Daphnia / Q000145:classification / Q000235:genetics* / Q000254:growth & development / Q000378:metabolism; D019143:Evolution, Molecular; D005260:Female; D008297:Male; D008969:Molecular Sequence Data; D009687:Nuclear Proteins / Q000737:chemistry / Q000235:genetics* / Q000378:metabolism*; D010802:Phylogeny; D019849:Sex Determination Processes
chemical_list: D009687:Nuclear Proteins