Younossi-Hartenstein A, Hartenstein V
Department of Biology, University of California, Los Angeles 90024.
Dev Biol. 1993 Aug;158(2):430-47. doi: 10.1006/dbio.1993.1201.
Developing sensory axons were studied in Drosophila embryos which carried a mutation in the trachealess and/or the twist gene. In these embryos, the tracheae and/or somatic muscles, which represent part of the substrate on which sensory axons normally grow, are absent. The results demonstrate that in each of these three mutant backgrounds, the majority of sensory nerves form normally. This indicates that neither the tracheae nor the somatic musculature is absolutely required for pathfinding of the embryonic sensory axons. On the other hand, the incidence of misrouted axons is significantly increased, most strongly in the trh, twi double mutant. Furthermore, axonal elongation is considerably slowed down, and sensory neurons which fail to send out an axon are frequent. We take our results to indicate that peripheral axons in the Drosophila embryo may be guided by multiple cues which, acting together, ensure the high fidelity of axonal pathways observed in normal development. The removal of one of these cues by itself does not necessarily lead to the total disability of axons to reach their target, although it enhances the frequency of error in pathfinding.
在携带无气管基因和/或扭曲基因发生突变的果蝇胚胎中，对正在发育的感觉轴突进行了研究。在这些胚胎中，作为感觉轴突正常生长的部分底物的气管和/或体壁肌肉缺失。结果表明，在这三种突变背景中的每一种情况下，大多数感觉神经都能正常形成。这表明，胚胎感觉轴突的路径寻找既不需要气管也不需要体壁肌肉组织。另一方面，轴突误路由的发生率显著增加，在无气管基因、扭曲基因双突变体中最为明显。此外，轴突伸长明显减慢，未能发出轴突的感觉神经元很常见。我们的研究结果表明，果蝇胚胎中的外周轴突可能由多种线索引导，这些线索共同作用，确保了在正常发育过程中观察到的轴突通路的高保真度。尽管去除其中一个线索会增加路径寻找错误的频率，但仅去除其中一个线索并不一定会导致轴突完全无法到达其目标。
