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到的信息的适当反应取决于感觉神经元和神经环下游效应神经元之间的精确连接。在发育过程中，延伸轴突是如何通过这个神经环来寻找它们的伴侣的，我们所知甚少。扩展的轴突如何解释位置信息，从而找到所需的突触伙伴？关注ASI化学感觉神经元在神经环中的适当位置的引导，突变筛选导致16个候选突变株的分离，这些突变株似乎具有ASI轴突引导和终止表型。这些突变定义了至少五个新的基因，命名为sax-10-14（感觉轴突引导）。已经观察到ASI轴突缺陷的四种主要表型类型，并且正在确定其他神经元的形态。为了方便sax基因的遗传分析和克隆，这些基因已经被定位，并且正在尝试通过注射cosmid和种系转化来挽救sax-10表型。最后，分析已知突变体对神经环中轴突引导的影响，将为轴突引导和神经环发育所需的机制提供见解。

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.