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Essential Roles for Ecdysone Signaling During Drosophila Mid-Embryonic Development
Tatiana Kozlova*, and
Carl S. Thummel
Although functions for the steroid hormone ecdysone during Drosophilametamorphosis have been well established, roles for the embryonicecdysone pulse remain poorly understood. We show that the EcR-USPecdysone receptor is first activated in the extraembryonic amnioserosa,implicating this tissue as a source of active ecdysteroids inthe early embryo. Ecdysone signaling is required for germ bandretraction and head involution, morphogenetic movements thatshape the first instar larva. This mechanism for coordinatingmorphogenesis during Drosophila embryonic development parallelsthe role of ecdysone during metamorphosis. It also providesan intriguing parallel with the role of mammalian extraembryonictissues as a critical source of steroid hormones during embryonicdevelopment.
Howard Hughes Medical Institute, Department of Human Genetics, University of Utah School of Medicine, 15 North 2030 East Room 5100, Salt Lake City, UT 841125331, USA.