Innervation of the ring gland of Drosophila melanogaster.
In insects, peptidergic neurons of the central nervous system regulate the synthesis of the main developmental hormones. Neuropeptides involved in this neuroendocrine cascade have been identified in lepidopterans and dictyopterans. Since these organisms are not suitable for genetic research, we identified peptidergic brain neurons innervating the ring gland in Drosophila melanogaster. In larvae of Drosophila, ecdysteroids and juvenile hormones are produced by the ring gland, which is composed of the prothoracic gland, the corpus allatum, and the corpora cardiaca. Using the GAL4 enhancer trap system, we mapped those neurons of the central nervous system that innervate the ring gland. Eleven groups of neurosecretory neurons and their target tissues were identified. Five neurons of the lateral protocerebrum directly innervate the prothoracic gland or corpus allatum cells of the ring gland and are believed to regulate ecdysteroid and juvenile hormone titers. Axons of the circadian pacemaker neurons project onto dendritic fields of these five neurons. This connection might be the neuronal substrate of the circadian rhythms of molting and metamorphosis in Drosophila. Most of the neurons presented here have not been described before. The enhancer trap lines labeling them will be valuable tools for the analysis of neuronal as well as genetic regulation in insect development.
Freie Universität Berlin, Institut für Biologie, Genetik, Berlin 14195, Germany. korge@genetik.fu-berlin.de
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D000818:Animals; D030801:Animals, Genetically Modified; D002940:Circadian Rhythm / Q000502:physiology; D004268:DNA-Binding Proteins; D004331:Drosophila melanogaster / Q000502:physiology*; D004742:Enhancer Elements, Genetic; D005656:Fungal Proteins / Q000235:genetics; D005838:Genotype; D049452:Green Fluorescent Proteins; D007301:Insect Hormones / Q000502:physiology; D007313:Insecta; D007814:Larva; D007915:Lepidoptera; D008164:Luminescent Proteins / Q000032:analysis; D009420:Nervous System / Q000166:cytology; D009424:Nervous System Physiological Phenomena; D009474:Neurons / Q000166:cytology / Q000502:physiology*; D009479:Neuropeptides / Q000502:physiology; D009490:Neurosecretory Systems / Q000166:cytology / Q000502:physiology; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors / Q000235:genetics
D004268:DNA-Binding Proteins; D005656:Fungal Proteins; C052130:GAL4 protein, S cerevisiae; D007301:Insect Hormones; D008164:Luminescent Proteins; D009479:Neuropeptides; D029701:Saccharomyces cerevisiae Proteins; D014157:Transcription Factors; D049452:Green Fluorescent Proteins