Przybyl Grace E, Wittes Julia, Greenwald Iva
Department of Biological Sciences, Columbia University, 1212 Amsterdam Avenue, New York, NY 10027, USA.
Department of Biological Sciences, Columbia University, 1212 Amsterdam Avenue, New York, NY 10027, USA.
Curr Biol. 2025 Jul 9. doi: 10.1016/j.cub.2025.05.028.
C. elegans displays remarkable developmental plasticity in response to environmental conditions. Under favorable conditions-for example, when food is abundant-larvae develop rapidly and continuously through four larval stages (L1-L4) separated by molts to reproductive adulthood. In adverse conditions, L1 larvae enter an alternative developmental pathway comprising a prolonged second larval stage ("L2d") and a prolonged molt into dauer diapause. Dauer larvae survive in a state of suspended development, with precursor cells maintained in a quiescent state, for many times the normal lifespan of a worm. If conditions improve, dauer larvae recover and resume reproductive development. A canonical insulin/insulin growth factor (IGF) signaling (IIS) pathway, comprising DAF-2/insulin receptor, the signal transducer AKT, and the transcription factor DAF-16/FoxO, is a major input into the global decision between reproductive development and dauer entry. Previous studies have suggested that IIS has a diffuse cellular focus for regulating dauer entry, but here we have identified a specific cellular focus by showing that low IIS activity in the somatic gonad is sufficient to promote entry into dauer diapause. Furthermore, we show that laser ablation of the germline precursors suppresses dauer entry when DAF-2 is depleted in the somatic gonad, demonstrating that the germ line acts with the somatic gonad as a signaling nexus. Our analysis implicates the somatic gonad as an endocrine organ for regulating a critical life history decision and identifies an unexpected role for the germ line in orchestrating the global somatic development of an individual.
秀丽隐杆线虫在应对环境条件时表现出显著的发育可塑性。在有利条件下，例如食物充足时，幼虫会迅速且持续地经历四个幼虫阶段（L1 - L4），各阶段之间通过蜕皮分隔，最终发育为生殖成熟的成虫。在不利条件下，L1幼虫进入另一种发育途径，包括延长的第二幼虫阶段（“L2d”）和延长的蜕皮进入 dauer 滞育期。Dauer 幼虫以发育暂停的状态存活，其前体细胞维持在静止状态，可存活蠕虫正常寿命的许多倍。如果条件改善，Dauer 幼虫会恢复并重新开始生殖发育。一条经典的胰岛素/胰岛素生长因子（IGF）信号传导（IIS）途径，包括DAF - 2/胰岛素受体、信号转导因子AKT和转录因子DAF - 16/FoxO，是生殖发育和进入 dauer 滞育这一全局决策的主要输入因素。先前的研究表明，IIS在调节进入 dauer 滞育方面具有广泛的细胞作用靶点，但在此我们通过表明体细胞性腺中低水平的IIS活性足以促进进入 dauer 滞育，确定了一个特定的细胞作用靶点。此外，我们表明，当体细胞性腺中DAF - 2缺失时，激光消融生殖系前体可抑制进入 dauer 滞育，这表明生殖系与体细胞性腺共同作为一个信号枢纽发挥作用。我们的分析表明体细胞性腺是调节关键生活史决策的内分泌器官，并确定了生殖系在协调个体整体体细胞发育中出人意料的作用。
