amino acids and tor signaling promote prothoracic gland growth and the initiation of larval molts in the tobacco hornworm manduca sexta氨基酸和tor信号促进前胸腺生长和起始的烟草天蛾的幼虫manduca sexta幼虫脱皮.pdfVIP

Amino Acids and TOR Signaling Promote Prothoracic Gland Growth and the Initiation of Larval Molts in the Tobacco Hornworm Manduca sexta 1 1 2 2 1 Karen Kemirembe , Kate Liebmann , Abigail Bootes , Wendy A. Smith , Yuichiro Suzuki * 1 Department of Biological Sciences, Wellesley College, Wellesley, Massachusetts, United States of America, 2 Department of Biology, Northeastern University, Boston, Massachusetts, United States of America Abstract Molting in arthropods is orchestrated by a series of endocrine changes that occur towards the end of an instar. However, little is understood about the mechanisms that trigger these endocrine changes. Here, nutritional inputs were manipulated to investigate the minimal nutritional inputs required for a Manduca sexta larva to initiate a molt. Amino acids were found to be necessary for a larva to molt, indicating the involvement of an amino acid sensitive pathway. Feeding rapamycin, an inhibitor of the target of rapamycin (TOR) signaling, delayed the onset of a molt and resulted in abnormally larger larvae. Rapamycin also suppressed the growth of the prothoracic glands relative to the whole body growth, and this was accompanied by suppression of ecdysone production and secretion. Higher doses of rapamycin also slowed the growth rate, indicating that TOR signaling also plays a role in systemic growth. TOR signaling therefore couples the nutritional status of the larva to the endocrine system to regulate the timing of a molt. Citation: Kemirembe K, Liebmann K, Bootes A, Smith WA, Suzuki Y (2012) Amino Acids and TOR Signaling Promote Prothoracic Gland Growth and the Initiation of Larval Molts in the Tobacco Hornworm Manduca sexta. PLoS ONE 7(9): e44429. doi:10.1371/jou