Regulation Mechanism of Gene Expression by Insect Juvenile Hormone and Identification of Juvenile Hormone Receptor

点击翻译按钮获取中文摘要

Insect juvenile hormone (JH) is an important hormone for insect to regulate metamorphosis, diapause, polymorphism, reproduction and so on. Molecular mechanism of mode of action of JH have been studied, and shown to regulate the expression of genes related to those physiological phenomena. However, JH receptor has not been identified and isolated.A PCR approach has been used to isolate, form Bombyx mori, a cDNA encoding a novel orphan receptor (GRF) that is most closely related to Bombyx bFTZ-F1 and to the vertebrate germ cell nuclear factor. The major GRF mRNA is detected in most tissues as an 8-kb transcript whose amount follows the circulating ecdysteroid concentration with a delay. The expression pattern of GRF is similar to that of the Bombyx homologue of the Drosophila early late gene DHR3, and precedes that of bFTZ-F1 in all stages and tissues examined. The GRF protein is thus likely to be required in many tissues, but in a temporally restricted manner suggesting that GRF has a well-defined function in the ecdysteroid-induced transcription cascade. The GRF protein binds in vitro to a single oestrogen receptor half-site AGGTCA preceded by a 50 -TCA extension, and is therefore a potential co-regulator of the orphan receptors bFTZ-F1 and DHR39.