DISTINCT ROLES FOR ADHESION MOLECULES DURING INNERVATION OF EMBRYONIC CHICK MUSCLE
DISTINCT ROLES FOR ADHESION MOLECULES DURING INNERVATION OF EMBRYONIC CHICK MUSCLE
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DOI：
10.1016/0012-1606(88)90358-2
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发表时间：
1988-12-01
影响因子：
2.7
通讯作者：
RUTISHAUSER, U
中科院分区：
文献类型：
--
作者：
LANDMESSER, L;DAHM, L;RUTISHAUSER, U
体外研究表明，细胞粘附分子NCAM和G4/L1有助于神经发育过程中的各种事件。我们已经直接测试了这些分子在胚胎鸡髂腓肌的初始神经长入和分支的过程中所发挥的作用，通过在卵内注射特异性粘连阻断抗体和分析所得到的神经分支模式在肌肉整体坐骑。针对这两种分子的抗体产生轴突解束，这导致了增强的横向投影到肌肉的快速区域。在抗G4/L1的情况下，我们还观察到从慢区中的神经干形成的侧支的数量大量增加，以及快区中的神经分支的增强。相反，抗NCAM产生了显着减少的数量和长度的侧支在慢区，并减少在快区的神经分支。注射内唾液酸酶后，神经分支得到类似的减少，内唾液酸酶从NCAM中除去唾液酸，并且观察到其增强纤维-纤维附着，推测是通过增加细胞粘附。基于它们的体外生化特性和它们的体内分布，NCAM和G4/L1都能够促进轴突-轴突粘附相互作用，而NCAM预计也会促进轴突-肌管相互作用。事实上，我们的观察表明，这两种粘附分子在肌肉神经支配过程中发挥着不同但互补的作用，特别是，NCAM和G4/L1以解剖学上不同的方式影响轴突-轴突成束，以调节神经分支的总体模式，并且NCAM介导的轴突-肌管相互作用对于在该肌肉的快区和慢区中获得神经分支的正常定型模式是必要的。
In vitro studies have suggested that the cell adhesion molecules NCAM and G4/L1 contribute to a variety of events during neural development. We have directly tested the role played by these molecules in the process of initial nerve ingrowth and ramification in the embryonic chick iliofibularis muscle by in ovo injections of specific adhesion-blocking antibodies and analysis of the resultant nerve branching pattern in muscle whole mounts. Antibodies against both molecules produced axonal defasciculation, which resulted in an enhanced transverse projection to the fast region of the muscle. In the case of anti-G4/L1, we also observed a large increase in the number of side branches that form from nerve trunks in the slow region and an enhancement of nerve branching in the fast region. Conversely, anti-NCAM produced a striking decrease in both the number and length of side branches in the slow region, and a reduction in nerve branching in the fast region. A similar reduction of nerve branching was obtained following injection of an endosialidase, which removes sialic acid from NCAM, and which was observed to enhance fiber-fiber apposition, presumably by increasing cell adhesion. Based on their biochemical properties in vitro and their in vivo distribution, both NCAM and G4/L1 are in a position to contribute to axon-axon adhesive interactions, whereas NCAM would be expected to also promote axon-myotube interactions. Our observations in fact indicate that these two adhesion molecules play different but complementary roles during muscle innervation and, specifically, that axon-axon fasciculation is influenced by both NCAM and G4/L1 in an anatomically distinct manner to regulate the overall pattern of nerve branching and that NCAM-mediated axon-myotube interactions are necessary for the attainment of the normal stereotyped pattern of nerve branching in both fast and slow regions of this muscle.