The control of body and organ growth is essential for the development of adults with proper size and proportions, which is important for survival and reproduction. In animals, adult body size is determined by the rate and duration of juvenile growth, which are influenced by the environment. In nutrient-scarce environments in which more time is needed for growth, the juvenile growth period can be extended by delaying maturation, whereas juvenile development is rapidly completed in nutrient-rich conditions. This flexibility requires the integration of environmental cues with developmental signals that govern internal checkpoints to ensure that maturation does not begin until sufficient tissue growth has occurred to reach a proper adult size. The Target of Rapamycin (TOR) pathway is the primary cell-autonomous nutrient sensor, while circulating hormones such as steroids and insulin-like growth factors are the main systemic regulators of growth and maturation in animals. We discuss recent findings in Drosophila melanogaster showing that cell-autonomous environment and growth-sensing mechanisms, involving TOR and other growth-regulatory pathways, that converge on insulin and steroid relay centers are responsible for adjusting systemic growth, and development, in response to external and internal conditions. In addition to this, proper organ growth is also monitored and coordinated with whole-body growth and the timing of maturation through modulation of steroid signaling. This coordination involves interorgan communication mediated by Drosophila insulin-like peptide 8 in response to tissue growth status. Together, these multiple nutritional and developmental cues feed into neuroendocrine hubs controlling insulin and steroid signaling, serving as checkpoints at which developmental progression toward maturation can be delayed. This review focuses on these mechanisms by which external and internal conditions can modulate developmental growth and ensure proper adult body size, and highlights the conserved architecture of this system, which has made Drosophila a prime model for understanding the coordination of growth and maturation in animals.

中文翻译：

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体型调节和生长控制。


身体和器官生长的控制对于成体发育成适当的大小和比例至关重要，这对于生存和繁殖很重要。在动物中，成年体的大小由幼年生长的速度和持续时间决定，而幼年生长的速度和持续时间受到环境的影响。在营养稀缺的环境中，生长需要更多的时间，幼鱼的生长期可以通过延迟成熟来延长，而在营养丰富的条件下，幼鱼的发育很快完成。这种灵活性需要将环境线索与控制内部检查点的发育信号相结合，以确保在组织充分生长以达到适当的成年尺寸之前不会开始成熟。雷帕霉素靶点 (TOR) 途径是主要的细胞自主营养传感器，而类固醇和胰岛素样生长因子等循环激素是动物生长和成熟的主要系统调节剂。我们讨论了黑腹果蝇的最新发现，这些发现表明，细胞自主环境和生长传感机制（涉及 TOR 和其他生长调节途径）汇聚于胰岛素和类固醇中继中心，负责调整系统生长和发育，以响应外部环境。和内部条件。除此之外，还通过调节类固醇信号传导来监测适当的器官生长并与全身生长和成熟时间协调。这种协调涉及果蝇胰岛素样肽 8 介导的器官间通讯，以响应组织生长状态。 这些多种营养和发育线索共同进入控制胰岛素和类固醇信号传导的神经内分泌中枢，充当可以延迟成熟发育进程的检查点。本综述重点关注外部和内部条件调节发育生长并确保适当的成年体型的机制，并强调该系统的保守结构，这使果蝇成为了解动物生长和成熟协调的主要模型。