Involvement of the Cytoplasmic C-Terminal Domain of Connexin43 in Neuronal Migration
Involvement of the Cytoplasmic C-Terminal Domain of Connexin43 in Neuronal Migration
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DOI：
10.1523/jneurosci.5025-08.2009
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发表时间：
2009-02-18
影响因子：
5.3
通讯作者：
Naus, Christian C.
中科院分区：
文献类型：
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作者：
Cina, Cima;Maass, Karen;Naus, Christian C.
在大脑发育过程中，年轻神经元在从新皮质的心室区（VZ）迁移到皮质板（CP）时与放射状胶质细胞密切相关。先前已经表明，间隙连接是这种迁移正常发生所必需的，但确切的机制仍然存在疑问。在这里，我们使用由巢蛋白启动子驱动的 Cre 重组酶，有条件地敲除小鼠中 connexin43 (Cx43) 基因的 floxed 编码 DNA。 VZ 中的放射状胶质细胞通常表达连接蛋白 43。它们经历分裂，产生神经元和星形胶质细胞，并充当它们产生的子细胞的迁移指南。基于组织学分析，我们建议从放射状胶质细胞中去除 Cx43 会改变小鼠新皮质的正常分层。为了监测发育过程中的新生神经元，我们使用子宫内电穿孔将含有由神经元（T α1 微管蛋白）启动子驱动的绿色荧光蛋白的质粒引入胚胎新皮质。转染的迁移神经元保留在 Cx43 条件敲除 (Cx43cKO) 动物的 VZ/中间区 (IZ) 中，而在 Cx43(fl/fl) 小鼠中，神经元通过 IZ 迁移到 CP，表明从巢蛋白阳性细胞中删除 Cx43 会破坏神经元迁移。我们能够通过将巨细胞病毒-Cx43 表达质粒电穿孔到胚胎皮层来挽救 Cx43cKO 神经元的迁移。相比之下，Cx43 的 C 端截短形式未能挽救神经元迁移。此外，Cx43(K258stop) 小鼠（其中 Cx43 缺乏细胞质 C 末端结构域的最后 125 个氨基酸残基）给出了与 Cx43cKO 小鼠相似的结果。这项研究表明，Cx43 C 端结构域的缺失会改变新皮质中的神经元迁移。
During brain development, young neurons closely associate with radial glial while migrating from the ventricular zone (VZ) to the cortical plate (CP) of the neocortex. It has been shown previously that gap junctions are needed for this migration to occur properly, but the precise mechanism responsible is still in question. Here, we used Cre recombinase, driven by the nestin promoter, to conditionally knock-out a floxed coding DNA of the connexin43 (Cx43) gene in mice. Radial glia in the VZ normally express connexin43. They undergo divisions that produce neurons and astrocytes and serve as migratory guides for the daughter cells that they produce. Based on histological analysis, we suggest that removing Cx43 from radial glia alters the normal lamination of the mouse neocortex. To monitor newborn neurons during development, we introduced a plasmid containing green fluorescent protein driven by a neuronal (T alpha 1 tubulin) promoter into the embryonic neocortex using in utero electroporation. The transfected migrating neurons remain in the VZ/intermediate zone (IZ) of the Cx43 conditional knock-out (Cx43cKO) animals, whereas in Cx43(fl/fl) mice, neurons migrate through the IZ into the CP, indicating that deletion of Cx43 from nestin-positive cells disrupts neuronal migration. We were able to rescue migration of Cx43cKO neurons by electroporating a cytomegalovirus-Cx43 expression plasmid into the embryonic cortex. In contrast, a C-terminal truncated form of Cx43 failed to rescue neuronal migration. In addition, Cx43(K258stop) mice, in which Cx43 lacks the last 125 amino acid residues of the cytoplasmic C-terminal domain, gave results similar to those seen with the Cx43cKO mice. This study illustrates that deletion of the C-terminal domain of Cx43 alters neuronal migration in the neocortex.