Development, Evolution and the Environment Lab, Instituto Gulbenkian de Ciência, Fundação Calouste Gulbenkian Oerias, Portugal.
Front Endocrinol (Lausanne). 2012 Apr 3;3:49. doi: 10.3389/fendo.2012.00049. eCollection 2012.
OVER THE PAST TWO DECADES, FUNDAMENTAL STRIDES IN PHYSIOLOGY AND GENETICS HAVE ALLOWED US TO FINALLY GRASP THE DEVELOPMENTAL MECHANISMS REGULATING BODY SIZE, PRIMARILY IN ONE MODEL ORGANISM: the fruit fly Drosophila melanogaster. In Drosophila, as in all animals, final body size is regulated by the rate and duration of growth. These studies have identified important roles for the insulin and the target of rapamycin (TOR) signaling pathways in regulating the growth rate of the larva, the stage most important in determining final adult size. Furthermore, they have shown that the insulin/TOR pathway interacts with hormonal systems, like ecdysone and juvenile hormone, to regulate the timing of development and hence the duration of growth. This interaction allows the growing larvae to integrate cues from the environment with environmentally sensitive developmental windows to ensure that optimal size and proportions are reached given the larval rearing conditions. Results from this work have opened up new avenues of studies, including how environmental cues are integrated to regulate developmental time and how organs maintain proportional growth. Other researchers interested in the evolution of body size are beginning to apply these results to studies of body size evolution and the generation of allometry. With these new findings, and with the developments to come, the field of size control finds itself in the fortunate position of finally being able to tackle century old questions of how organisms achieve final adult size and proportions. This review discusses the state of the art of size control from a Drosophila perspective, and outlines an approach to resolving outstanding issues.
在过去的二十年中，生理学和遗传学的基础研究使我们终于能够理解控制体型的发育机制，主要是在一种模式生物中：黑腹果蝇 Drosophila melanogaster。在果蝇中，与所有动物一样，最终体型大小受生长速度和时间的调节。这些研究确定了胰岛素和雷帕霉素靶蛋白（TOR）信号通路在调节幼虫生长速度方面的重要作用，而幼虫阶段是决定最终成虫体型的最重要阶段。此外，它们还表明，胰岛素/TOR 途径与激素系统（如蜕皮激素和保幼激素）相互作用，以调节发育的时间，从而调节生长的时间。这种相互作用使正在生长的幼虫能够将环境线索与对环境敏感的发育窗口整合起来，以确保在给定的幼虫饲养条件下达到最佳的体型和比例。这些研究结果开辟了新的研究途径，包括环境线索如何被整合以调节发育时间以及器官如何保持比例生长。其他对体型进化感兴趣的研究人员开始将这些结果应用于体型进化和异速生长的研究。随着这些新发现的出现，以及未来的发展，体型控制领域终于能够解决生物体如何达到最终成年体型和比例的百年老问题。这篇综述从果蝇的角度讨论了体型控制的最新进展，并概述了解决未决问题的方法。
