Laboratory of Biology, Sapporo Campus, Hokkaido University of Education, Sapporo, 002-8502, Japan.
Advanced ICT Research Institute, National Institute of Information and Communications Technology, Kobe, 651-2492, Japan.
Sci Rep. 2024 Feb 14;14(1):3740. doi: 10.1038/s41598-024-54295-3.
Drosophila melanogaster has a pair of male-specific muscles called the muscle of Lawrence (MOL) in abdominal segment 5 (A5) of adult flies. The MOL is produced only when its innervating motoneuron expresses FruitlessM (FruM) neural masculinizing proteins. We show that MOL induction is hampered by: (1) silencing electrical activities in the motoneuron, (2) blocking vesicular release from the motoneuron, and (3) knocking down Activin ß (Actß) in the motoneuron or knocking down Actß signaling pathway components in the myoblasts. Our timelapse live imaging of the developing neuromuscular system reveals that, upon contact with the presumptive MOL, the motoneuronal axon retracts concomitant with the progression of MOL degeneration resulting from neural silencing. We conclude that MOL formation depends on the bidirectional trophic interactions between pre- and postsynaptic cells, with motoneuron-derived Actß playing an inducing role in MOL formation.
果蝇的第 5 个腹节（A5）有一对雄性特有的肌肉，称为劳伦斯肌肉（MOL）。只有当其支配的运动神经元表达 FruM（FruitlessM）神经雄性化蛋白时，MOL 才会产生。我们发现，MOL 的诱导受到以下因素的阻碍：（1）运动神经元的电活动沉默，（2）阻断运动神经元的囊泡释放，以及（3）敲低运动神经元中的激活素 ß（Actß）或敲低肌母细胞中的 Actß 信号通路成分。我们对发育中的神经肌肉系统的延时实时成像显示，在与推定的 MOL 接触后，运动神经元轴突回缩，同时伴随着由于神经沉默导致的 MOL 退化的进展。我们得出结论，MOL 的形成取决于前突触和后突触细胞之间的双向营养相互作用，运动神经元衍生的 Actß 在 MOL 的形成中发挥诱导作用。
