Uchida N, Shimamura K, Miyatani S, Copeland N G, Gilbert D J, Jenkins N A, Takeichi M
Department of Biophysics, Faculty of Science, Kyoto University, Japan.
Dev Biol. 1994 May;163(1):75-85. doi: 10.1006/dbio.1994.1124.
We isolated cDNAs encoding mouse homologues of chicken alpha N-catenin, a protein associated with the cadherin cell adhesion molecules, and identified two isoforms of this protein. One isoform (alpha N-catenin I) was identical to the chicken alpha N-catenin that had previously been identified, and the other (alpha N-catenin II) differed in having a 48-amino acid insertion in its C-terminal region. The ratio of the two isoforms changed during development; the isoform II was more abundant than the other in earlier embryonic stages, whereas isoform I was predominant in the adult stage. Immunostaining and in situ hybridization analyses revealed that the mouse alpha N-catenin was expressed almost exclusively in the nervous system. During embryogenesis, alpha N-catenin was first detected in nerve fibers of cranial and dorsal root ganglia and also in early neurons in the neural tube, including motor neurons. Thereafter, the expression of this protein occurred in various regions of the nervous system. Neurons, in general, strongly expressed alpha N-catenin, especially in their axonal fibers. On the other hand, the expression in glial cells varied with the region. For example, the ependymal layers of the neural tube generally expressed low levels of alpha N-catenin except at the inner limiting membrane facing the central canal, whereas the floor and roof plate exhibited strong expression of this protein at various portions of the central nervous system. The choroid plexus was devoid of alpha N-catenin. In the alpha N-catenin-negative regions, another subtype of alpha-catenin, alpha E-catenin, was expressed. Concerning nonneural tissues, alpha N-catenin was expressed only in some local mesenchymal cell clusters and the lens fibers. These results suggest that alpha N-catenin plays specific roles in neural cell-cell interactions. We also localized the mouse alpha N-catenin gene to chromosome 6.
我们分离出了编码鸡αN-连环蛋白小鼠同源物的cDNA，αN-连环蛋白是一种与钙黏蛋白细胞黏附分子相关的蛋白质，并鉴定出了该蛋白的两种异构体。一种异构体（αN-连环蛋白I）与先前鉴定出的鸡αN-连环蛋白相同，另一种（αN-连环蛋白II）的不同之处在于其C末端区域有一个48个氨基酸的插入片段。两种异构体的比例在发育过程中发生变化；异构体II在早期胚胎阶段比另一种更丰富，而异构体I在成年阶段占主导地位。免疫染色和原位杂交分析表明，小鼠αN-连环蛋白几乎只在神经系统中表达。在胚胎发生过程中，αN-连环蛋白首先在颅神经节和背根神经节的神经纤维以及神经管中的早期神经元（包括运动神经元）中被检测到。此后，该蛋白在神经系统的各个区域表达。一般来说，神经元强烈表达αN-连环蛋白，尤其是在其轴突纤维中。另一方面，胶质细胞中的表达因区域而异。例如，神经管的室管膜层通常表达低水平的αN-连环蛋白，除了面对中央管的内界膜处，而底板和顶板在中枢神经系统的各个部分都强烈表达该蛋白。脉络丛中没有αN-连环蛋白。在αN-连环蛋白阴性区域，表达了α-连环蛋白的另一种亚型，αE-连环蛋白。关于非神经组织，αN-连环蛋白仅在一些局部间充质细胞簇和晶状体纤维中表达。这些结果表明，αN-连环蛋白在神经细胞间相互作用中发挥特定作用。我们还将小鼠αN-连环蛋白基因定位到了6号染色体上。
