Innate behaviors consist of a succession of genetically-hardwired motor and physiological subprograms that can be coupled to drastic morphogenetic changes. How these integrative responses are orchestrated is not completely understood. Here, we provide insight into these mechanisms by studying pupariation, a multi-step innate behavior of fly larvae that is critical for survival during metamorphosis. We find that the steroid-hormone ecdysone triggers parallel pupariation neuromotor and morphogenetic subprograms, which include the induction of the relaxin-peptide hormone, Dilp8, in the epidermis. Dilp8 acts on six Lgr3-positive thoracic interneurons to couple both subprograms in time and to instruct neuromotor subprogram switching during behavior. Our work reveals that interorgan feedback gates progression between subunits of an innate behavior and points to an ancestral neuromodulatory function of relaxin signaling.

中文翻译：

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肽介导的器官间串扰的先天行为序列进展

先天行为由一系列遗传上硬性的运动和生理子程序组成，这些子程序可以与剧烈的形态发生变化耦合。这些整合的响应是如何编排的还没有被完全理解。在这里，我们通过研究幼虫（蝇multi幼虫的多步先天行为对变态过程中的生存至关重要）来提供对这些机制的见解。我们发现类固醇激素蜕皮激素触发平行的pu肌神经运动和形态发生子程序，其中包括在表皮中诱导松弛素肽激素Dilp8。Dilp8作用于六个Lgr3阳性胸腔中神经元，以及时耦合两个子程序，并在行为过程中指示神经运动子程序切换。