title: Transcription factor E74A affects the ecdysone titer by regulating the expression of the EO gene in the silkworm, Bomby mori.
abstract: The formation of ecdysone pulse in insects is synergistically controlled by its biosynthesis and degradation. Previous studies have revealed the feedback regulation of the prothoracic gland (PG) activity to affect the hormone synthesis. However, the molecular regulatory mechanism of the ecdysone degradation is still unclear. In this study, we showed that ecdysone oxidase (EO) gene encoding a hormone metabolism enzyme was also induced by hormone itself in the domestic silkworm, Bombyx mori. Furthermore, luciferase reporter, chromatin immunoprecipitation and electrophoretic mobility shift assays showed that ecdysone inducible transcription factor E74A could bind to the cis-regulatory elements of the EO gene. Then, down-regulating the expression of the E74A by RNA interference (RNAi) decreased the expression of the EO gene and caused a higher ecdysone titer compared with the control. Thus, our results demonstrated a new feedback regulation degradation (EO) pathway controlled by ecdysone itself through transcription factor E74A, expanding the knowledge about the regulatory system that determines the formation of ecdysone pulse.
authors.affiliation: Laboratory of Evolutionary and Functional Genomics, School of Life Sciences, Chongqing University, Chongqing 401331, China. Electronic address: sunwei077@cqu.edu.cn.
authors.forename: Wei
authors.initials: W
authors.lastname: Sun
authors.affiliation: Laboratory of Evolutionary and Functional Genomics, School of Life Sciences, Chongqing University, Chongqing 401331, China.
authors.forename: Cheng-Fang
authors.initials: CF
authors.lastname: Wang
authors.affiliation: Laboratory of Evolutionary and Functional Genomics, School of Life Sciences, Chongqing University, Chongqing 401331, China.
authors.forename: Ze
authors.initials: Z
authors.lastname: Zhang
mesh_terms: D015096:3-Hydroxysteroid Dehydrogenases / Q000235:genetics*; D000818:Animals; D012831:Bombyx / Q000235:genetics*; D002843:Chromatin / Q000235:genetics; D015536:Down-Regulation / Q000235:genetics; D004440:Ecdysone / Q000235:genetics*; D006728:Hormones / Q000235:genetics; D019476:Insect Proteins / Q000235:genetics*; D012045:Regulatory Sequences, Nucleic Acid / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic / Q000235:genetics
chemical_list: D002843:Chromatin; D006728:Hormones; D019476:Insect Proteins; D014157:Transcription Factors; D004440:Ecdysone; D015096:3-Hydroxysteroid Dehydrogenases; C020096:ecdysone oxidase
keywords: Ecdysone; Ecdysone oxidase (EO); RNA interference; Silkworm; Transcription factor E74A