title: Ecdysteroid biosynthesis in workers of the European honeybee Apis mellifera L.
abstract: We previously reported preferential expression of genes for ecdysteroid signaling in the mushroom bodies of honeybee workers, suggesting a role of ecdysteroid signaling in regulating honeybee behaviors. The organs that produce ecdysteroids in worker honeybees, however, remain unknown. We show here that the expression of neverland and Non-molting glossy/shroud, which are involved in early steps of ecdysteroid synthesis, was enhanced in the ovary, while the expression of CYP306A1 and CYP302A1, which are involved in later steps of ecdysone synthesis, was enhanced in the brain, and the expression of CYP314A1, which is involved in converting ecdysone into active 20-hydroxyecdysone (20E), was enhanced in the brain, fat body, and ovary. In in vitro organ culture, a significant amount of ecdysteroids was detected in the culture medium of the brain, fat body, and hypopharyngeal glands. The ecdysteroids detected in the culture medium of the fat body were identified as ecdysone and 20E. These findings suggest that, in worker honeybees, cholesterol is converted into intermediate ecdysteroids in the ovary, whereas ecdysone is synthesized and secreted mainly by the brain and converted into 20E in the brain and fat body.
authors.affiliation: Department of Biological Sciences, Graduate School of Science, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo, Japan.
authors.forename: Yurika
authors.initials: Y
authors.lastname: Yamazaki
authors.forename: Makoto
authors.initials: M
authors.lastname: Kiuchi
authors.forename: Hideaki
authors.initials: H
authors.lastname: Takeuchi
authors.forename: Takeo
authors.initials: T
authors.lastname: Kubo
mesh_terms: D000818:Animals; D001516:Bees / Q000166:cytology / Q000201:enzymology / Q000235:genetics; D002851:Chromatography, High Pressure Liquid; D017077:Culture Media, Conditioned; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D004440:Ecdysone / Q000096:biosynthesis* / Q000235:genetics; D004441:Ecdysterone / Q000096:biosynthesis* / Q000235:genetics; D005060:Europe; D005216:Fat Body / Q000166:cytology / Q000201:enzymology; D005260:Female; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology; D019476:Insect Proteins / Q000235:genetics / Q000378:metabolism*; D009924:Organ Culture Techniques; D009928:Organ Specificity; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D011863:Radioimmunoassay; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000502:physiology; D013250:Steroid Hydroxylases / Q000235:genetics / Q000378:metabolism*
chemical_list: D017077:Culture Media, Conditioned; D019476:Insect Proteins; D012333:RNA, Messenger; D004440:Ecdysone; D004441:Ecdysterone; D003577:Cytochrome P-450 Enzyme System; D013250:Steroid Hydroxylases