RRC ID 459
著者 Makka T, Seino A, Tomita S, Fujiwara H, Sonobe H.
タイトル A possible role of 20-hydroxyecdysone in embryonic development of the silkworm Bombyx mori.
ジャーナル Arch Insect Biochem Physiol
Abstract It has been well established that eggs of insects, including those of the silkworm Bombyx mori, contain various ecdysteroids and the amounts of these ecdysteroids fluctuate during embryonic development. In order to know the function of egg ecdysteroids in embryonic development of B. mori, we examined the biological activities of various egg ecdysteroids by in vitro ligand-binding assay and bioassay using B. mori eggs. First, using the ecdysteroid receptor of B. mori (BmEcR-B1/BmUSP heterodimer) prepared by yeast and Escherichia coli expression systems, the interaction between the ecdysteroid receptor and various egg ecdysteroids of B. mori was analyzed. The relative binding affinities of egg ecdysteroids to the BmEcR-B1/BmUSP heterodimer decreased in the order of 20-hydroxyecdysone > 2-deoxy-20-hydroxyecdysone > 22-deoxy-20-hydroxyecdysone > ecdysone > 2-deoxyecdysone > ecdysone 22-phosphate. Next, several egg ecdysteroids of B. mori were injected into the prospective diapause eggs, which show a very low level of free ecdysteroids at the onset of embryonic diapause (gastrula stage). Approximately 7% of them (P < 0.002, chi(2)-test) developed beyond the gastrula stage without entering diapause by the injection of 20-hydroxyecdysone (25 ng/egg). In contrast, the injection of other ecdysteroids was not effective in inducing embryonic development. These results suggest that 20-hydroxyecdysone, via the ecdysteroid receptor, is responsible for the developmental difference between diapause and non-diapause in B. mori embryos. Furthermore, it was suggested that continuous supply of 20-hydroxyecdysone may be required to induce embryonic development.
巻・号 51(3)
ページ 111-20
公開日 2002-11-1
DOI 10.1002/arch.10055
PMID 12386839
MeSH Animals Bombyx / drug effects Bombyx / embryology* Dimerization Ecdysteroids / metabolism Ecdysterone / analogs & derivatives Ecdysterone / metabolism* Ovum / metabolism Protein Binding Receptors, Steroid / metabolism Recombinant Fusion Proteins / metabolism
IF 1.536
引用数 31
WOS 分野 ENTOMOLOGY PHYSIOLOGY BIOCHEMISTRY & MOLECULAR BIOLOGY
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