foxo regulates organ-specific phenotypic plasticity in drosophila在果蝇foxo调节瀑特异表型可塑性.pdfVIP

FOXO Regulates Organ-Specific Phenotypic Plasticity In Drosophila 1 2 1 1 Hui Yuan Tang , Martha S. B. Smith-Caldas , Michael V. Driscoll , Samy Salhadar , Alexander W. Shingleton1,3* 1 Department of Zoology, Michigan State University, East Lansing, Michigan, United States of America, 2 Division of Biology, Kansas State University, Manhattan, Kansas, United States of America, 3 BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, Michigan, United States of America Abstract Phenotypic plasticity, the ability for a single genotype to generate different phenotypes in response to environmental conditions, is biologically ubiquitous, and yet almost nothing is known of the developmental mechanisms that regulate the extent of a plastic response. In particular, it is unclear why some traits or individuals are highly sensitive to an environmental variable while other traits or individuals are less so. Here we elucidate the developmental mechanisms that regulate the expression of a particularly important form of phenotypic plasticity: the effect of developmental nutrition on organ size. In all animals, developmental nutrition is signaled to growing organs via the insulin-signaling pathway. Drosophila organs differ in their size response to developmental nutrition and this reflects differences in organ-specific insulin-sensitivity. We show that this variation in insulin-sensitivity is regulated at the level of the forkhead transcription factor FOXO, a negative growth regulator that is activated when nutrition and insulin signaling are low. Individual organs appear to attenuate growth suppression in response to low nutrition through an organ-specific reduction in FOXO expression, thereby reducing