Copenhaver P F, Horgan A M, Nichols D C, Rasmussen M A
Department of Cell Biology and Anatomy, Oregon Health Sciences University, Portland 97201, USA.
J Neurobiol. 1995 Apr;26(4):461-84. doi: 10.1002/neu.480260402.
The heterotrimeric G proteins are a conserved family of guanyl nucleotide-binding proteins that appear in all eukaryotic cells but whose developmental functions are largely unknown. We have examined the developmental expression of representative G proteins in the developing nervous system of the moth Manduca sexta. Using affinity-purified antisera against different G alpha subunits, we found that each of the G proteins exhibited distinctive patterns of expression within the developing central nervous system (CNS), and that these patterns underwent progressive phases of spatial and temporal regulation that corresponded to specific aspects of neuronal differentiation. Several of the G proteins examined (including Gs alpha and G(o) alpha) were expressed in an apparently ubiquitous manner in all neurons, but other proteins (including Gi alpha) were ultimately confined to a more restricted subset of cells in the mature CNS. Although most of the G proteins examined could be detected within the central ganglia, only G(o) alpha-related proteins were seen in the developing peripheral nerves; manipulations of G protein activity in cultured embryos suggested that this class of G protein may contribute to the regulation of neuronal motility during axonal outgrowth. G(o) alpha-related proteins were also localized to the developing axons and terminals of the developing adult limb during metamorphosis. These intracellular signaling molecules may, therefore, play similar developmental roles in both the embryonic and postembryonic nervous system.
异源三聚体G蛋白是一类保守的鸟苷核苷酸结合蛋白家族，存在于所有真核细胞中，但其发育功能大多未知。我们研究了代表性G蛋白在烟草天蛾发育中的神经系统中的发育表达情况。使用针对不同Gα亚基的亲和纯化抗血清，我们发现每种G蛋白在发育中的中枢神经系统（CNS）内都表现出独特的表达模式，并且这些模式经历了空间和时间调节的渐进阶段，这与神经元分化的特定方面相对应。所检测的几种G蛋白（包括Gsα和G(o)α）在所有神经元中均以明显普遍的方式表达，但其他蛋白（包括Giα）最终局限于成熟CNS中更有限的细胞亚群。尽管所检测的大多数G蛋白可在中枢神经节中检测到，但在发育中的外周神经中仅可见与G(o)α相关的蛋白；对培养胚胎中G蛋白活性的操作表明，这类G蛋白可能在轴突生长过程中有助于调节神经元的运动性。在变态过程中，与G(o)α相关的蛋白也定位于发育中的成虫肢体的发育轴突和终末。因此，这些细胞内信号分子可能在胚胎期和胚后神经系统中发挥相似的发育作用。
