Cell adhesion molecules regulate guidance of dorsal root ganglion axons in the marginal zone and their invasion into the mantle layer of embryonic spinal cord.
Cell adhesion molecules regulate guidance of dorsal root ganglion axons in the marginal zone and their invasion into the mantle layer of embryonic spinal cord.
复制标题
细胞粘附分子调节边缘区背根神经节轴突的引导及其对胚胎脊髓套层的侵入。
DOI：
10.1006/dbio.1997.8742
复制
发表时间：
1997
期刊：
影响因子：
--
通讯作者：
Shirai,T
中科院分区：
文献类型：
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作者：
Shiga,T;Lustig,M;Grumet,M;Shirai,T
为了阐明背根神经节（DRG）轴突在脊髓背索中投射和侵入脊髓外套层靶区（前瞻性灰质）的调控机制，我们研究了DRG轴突与脊髓之间的相互作用。从鸡胚中分离DRG神经元，并在胚胎第5天（E5）或E9时在脊髓的低温恒温切片上培养1-2天。E5和E9 DRG神经元将神经突延伸到脊髓的边缘区（预期的白色物质）和套层（预期的灰质），表明这两个区域都允许神经突生长。E5 DRG神经突从外侧接近脊髓冰冻切片时，大多数神经突在边缘区行走，不侵犯套层。相反，大约一半的E9 DRG神经突穿过E9脊髓边缘区后进入套层。DRG神经突在脊髓边缘区和套层的生长模式与体内相应阶段的DRG轴突通路形成相似，DRG轴突在E6前仅在预期的背索中走行，到E9时进入套层（预期的背角）到达靶区。通过在培养基中加入特异性抗体来干扰Ng-CAM、Nr-CAM和axonin-1/SC2的功能，增加了DRG神经突进入E5脊髓套层的比例，这表明这些细胞粘附分子参与将DRG神经突保持在边缘区。结合Ng-CAM、Nr-CAM和axonin-1/SC2的表达，这些位于DRG轴突上的CAM可能在E6之前调节这些轴突在边缘区的引导，并且随后这些CAM的相对水平的降低可能允许DRG轴突侵入靶套层。
In order to elucidate the mechanisms regulating the projections of dorsal root ganglion (DRG) axons in the dorsal funiculus and invasion into target regions in the mantle layer (prospective gray matter) of the spinal cord, we examined the interactions between DRG axons and spinal cord. DRG neurons were dissociated from chick embryos and cultured for 1–2 days on cryostat sections of the spinal cord at embryonic day 5 (E5) or at E9. E5 and E9 DRG neurons extended neurites onto both marginal zone (prospective white matter) and mantle layer (prospective gray matter) of the spinal cord, suggesting that both of these regions are permissive for neurite growth. When E5 DRG neurites approached cryosections of E5 spinal cord from outside, most of them ran in the marginal zone without invading the mantle layer. In contrast, about half of E9 DRG neurites entered the mantle layer after crossing the marginal zone of E9 spinal cord. These growth patterns of DRG neurites on spinal marginal zone and mantle layer are similar to the pathway formation of DRG axons at comparable stagesin vivo;DRG axons run exclusively in the prospective dorsal funiculus before E6, and enter the mantle layer (prospective dorsal horn) to reach the target regions by E9. Perturbation of functions of Ng-CAM, Nr-CAM, and axonin-1/SC2 by adding the specific antibodies in the culture medium increased the ratio of DRG neurites entering the mantle layer of E5 spinal cord, suggesting that these cell adhesion molecules are involved in keeping DRG neurites in the marginal zone. Taken together with the expression of Ng-CAM, Nr-CAM, and axonin-1/SC2, these CAMs on DRG axons may regulate the guidance of these axons in the marginal zone before E6, and the subsequent decrease in the relative levels of these CAMs might allow DRG axons to invade the target mantle layer.