MECHANISMS OF SENSORY AXON GUIDANCE

蠕虫依靠味觉、触觉和嗅觉来感知和探索它们的环境。 对通过这些不同方式接收的信息的适当反应取决于神经环中感觉神经元和下游效应神经元之间的精确连接。 关于在发育过程中延伸的轴突如何通过这个神经环神经元迁移以找到它们的伴侣，人们知之甚少。延伸的轴突是如何解释位置信息，从而找到所需的突触伴侣的？ 专注于ASI化学感觉神经元在神经环中的适当位置的指导，突变体筛选导致分离出16个候选突变株，这些突变株似乎具有ASI轴突指导和终止表型。 这些突变定义了至少五个新的基因，命名为sax-10-14（感觉轴突导向）。四个主要的表型类的ASI轴突缺陷已被观察到和其他神经元的形态正在确定。 为了便于对sax基因进行遗传分析和克隆，已经对这些基因进行了定位，并且正在尝试通过粘粒注射和种系转化来挽救sax-10表型。 最后，分析已知的突变体对神经环中轴突导向的影响将提供关于轴突导向和神经环发育所需机制的见解。

Worms depend on taste, touch and smell to sense and explore their environment. Appropriate responses to information received through these different modalities depends on precise connectivity between sensory neurons and downstream effector neurons in the nerve ring. Little is known about how extending axons migrate through this nerve ring neuropil during development to find their partners. How is positional information interpreted by an extending axon so that desired synaptic partners are found? Focusing on the guidance of the ASI chemosensory neurons to their appropriate positions in the nerve ring, a mutant screen led to the isolation of 16 candidate mutant strains that appeared to have ASI axon guidance and termination phenotypes. These mutations define at least five new genes named sax-10-14 (sensory axon guidance). Four main phenotypic classes of ASI axon defects have been observed and the morphologies of other neurons are being determined. To facilitate genetic analysis and cloning of the sax genes, the genes have been mapped and attempts to rescue the sax-10 phenotype by cosmid injections and germline transformation are ongoing. Finally, analysis of known mutants for effects on axon guidance in the nerve ring will provide insight on what mechanisms are required for axon guidance and nerve ring development.