Organization and repression by juvenile hormone of a vitellogenin gene cluster in the crustacean, Daphnia magna.
Two Daphnia magna vitellogenin (VTG) genes in neighboring but opposite orientations were identified. One was the gene for DmagVTG1, a previously characterized VTG polypeptide with a superoxide dismutase (SOD)-like domain at its NH(2)-terminus [Kato et al., Gene 334 (2004) 157-165]. Both genes had a 17-exon and 16-intron structure in the same configuration. DmagVTG2, a polypeptide encoded by the other gene, also had a SOD-like domain at its NH(2)-terminus. The amino acid sequences of the two VTG domains were highly homologous (95.5% identity), while those of the SOD-like domains were less homologous (62.4% identity). The VTG domains are phylogenetically related to insect VTGs while the SOD-like domains are related to viral and bacterial SODs. The intergenic region of 2.6kb between the two genes contains sequences resembling known juvenile hormone (JH)-responsive and ecdysone-responsive elements. JH agonists, pyriproxyfen and fenoxycarb, strongly repressed the expression of VTG genes in neonate daphnids.
Tokishita
Shin-Ichi
S
Laboratory of Environmental and Molecular Biology, Environmental Science Division, School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1 Horinouchi, Hachioji, Tokyo 192-0392, Japan. shinichi@.ls.toyaku.ac.jp
Kato
Yasuhiko
Y
Kobayashi
Taku
T
Nakamura
Shuhei
S
Ohta
Toshihiro
T
Yamagata
Hideo
H