Matsumoto Ken-Ichi, Sawa Hirofumi, Sato Mami, Orba Yasuko, Nagashima Kazuo, Ariga Hiroyoshi
Department of Molecular Biology, Graduate School of Pharmaceutical Sciences, Hokkaido University, Kita 12, Nishi 6, Kita-ku, Sapporo 060-0812, Japan.
Acta Neuropathol. 2002 Nov;104(5):448-54. doi: 10.1007/s00401-002-0577-x. Epub 2002 Jun 19.
Tenascin-X (TNX) is an extracellular matrix protein that is highly expressed in the peripheral nervous system as well as muscular tissues, especially the heart and skeletal muscle. However, the expression manner and the physiological role of TNX in the peripheral nervous system have not been fully investigated. In this study, we elucidated its distribution in adult mouse sciatic nerves by immunohistochemical staining. TNX was found to be localized in the perineurium and the endoneurium of sciatic nerve fibers. To examine the physiological role of TNX, we investigated sciatic nerves of TNX-deficient mice that are viable and fertile and have no obvious deficits in general performance. The thickness of myelin sheaths and the size of the individual axons in these mice appeared normal. The ultrastructure of the sciatic nerves of TNX-deficient mice were similar to those of wild-type mice. Thus, the lack of a discernible phenotype in the sciatic nerves of TNX-deficient mice suggests that TNX has either a redundant or a very subtle function in the macromolecular organization in the peripheral nerve.
腱生蛋白-X（TNX）是一种细胞外基质蛋白，在外周神经系统以及肌肉组织中高表达，尤其是心脏和骨骼肌。然而，TNX在外周神经系统中的表达方式和生理作用尚未得到充分研究。在本研究中，我们通过免疫组织化学染色阐明了其在成年小鼠坐骨神经中的分布。发现TNX定位于坐骨神经纤维的神经束膜和神经内膜。为了研究TNX的生理作用，我们研究了TNX缺陷型小鼠的坐骨神经，这些小鼠能够存活且可育，一般行为表现无明显缺陷。这些小鼠的髓鞘厚度和单个轴突大小看起来正常。TNX缺陷型小鼠坐骨神经的超微结构与野生型小鼠相似。因此，TNX缺陷型小鼠坐骨神经中缺乏可识别的表型表明，TNX在外周神经的大分子组织中要么具有冗余功能，要么具有非常微妙的功能。
