Maintenance of neuronal positions in organized ganglia by SAX-7, a Caenorhabditis elegans homologue of L1
Maintenance of neuronal positions in organized ganglia by SAX-7, a Caenorhabditis elegans homologue of L1
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DOI：
10.1038/sj.emboj.7600621
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发表时间：
2005-04-06
期刊：
影响因子：
11.4
通讯作者：
Mori, I
中科院分区：
文献类型：
--
作者：
Sasakura, H;Inada, H;Mori, I
细胞粘附分子L1家族主要在神经系统中表达。人类L1突变导致神经元疾病，如HSAS、MASA和SPG 1。在这里，我们表明，萨克斯-7基因编码的L1同源线虫。在sax-7突变体中，神经节的组织和神经元的定位在成体阶段异常，但这些异常在早期幼虫阶段未观察到。sax-7突变体中神经元的错位是由与身体运动相关的机械力触发的。短型和长型的SAX-7在体外聚集实验中分别表现出强和弱的嗜同性粘附活性，这与它们在体内的不同活性有关。SAX-7在体内定位于神经元的质膜上。在sax-7突变体中，仅在单个神经元中表达SAX-7，细胞自主地恢复其正常的神经元位置。在两个不同的头部神经元的sax-7突变体的表达，导致这些神经元的强制附着。我们建议，嗜同性和嗜异性的相互作用的SAX-7是必不可少的维持神经元的位置在有组织的神经节。
The L1 family of cell adhesion molecules is predominantly expressed in the nervous system. Mutations in human L1 cause neuronal diseases such as HSAS, MASA, and SPG1. Here we show that sax-7 gene encodes an L1 homologue in Caenorhabditis elegans. In sax-7 mutants, the organization of ganglia and positioning of neurons are abnormal in the adult stage, but these abnormalities are not observed in early larval stage. Misplacement of neurons in sax-7 mutants is triggered by mechanical force linked to body movement. Short and long forms of SAX-7 exhibited strong and weak homophilic adhesion activities in in vitro aggregation assay, respectively, which correlated with their different activities in vivo. SAX-7 was localized on plasma membranes of neurons in vivo. Expression of SAX-7 only in a single neuron in sax-7 mutants cell-autonomously restored its normal neuronal position. Expression of SAX-7 in two different head neurons in sax-7 mutants led to the forced attachment of these neurons. We propose that both homophilic and heterophilic interactions of SAX-7 are essential for maintenance of neuronal positions in organized ganglia.