Mitrovic N, Schachner M
Department of Neurobiology, Swiss Federal Institute of Technology, Zurich, Switzerland.
J Neurosci Res. 1995 Dec;42(5):710-7. doi: 10.1002/jnr.490420514.
We have investigated the expression of tenascin-C (TN-C) in the somatosensory cortex of early postnatal mutant mice in which lacZ was reported to be expressed in place of tenascin (Saga et al.: Genes Dev 6:1821-1831, 1992). At both the mRNA and protein levels, TN-C was detected at levels lower in the mutant than in wild type animals by in situ hybridization and by immunocytochemistry using several poly- and monoclonal antibodies directed against mouse TN-C. The distribution of TN-C immunoreactivity in coronal sections was abnormal in that the barrel field boundaries in layer 4 of the somatosensory cortex could not be detected intracellularly in most cell bodies, including possibly also neurons. Western blot analysis of homogenates of brain tissue from early postnatal animals showed an abnormal pattern of protein bands immunoreactive for TN-C in mutant animals while beta-galactosidase migrated at its expected molecular weight without incorporation into fusion proteins with TN-C, suggesting disturbed splicing mechanisms. No gross disturbances in the patterning of barrel fields could be detected in the mutant mice as shown by Nissl staining. Our observations show that the mutant mouse designed to be nully disrupted for TN-C expression shows detectable and abnormal TN-C expression.
我们研究了出生后早期突变小鼠体感皮层中腱生蛋白-C（TN-C）的表达情况，据报道在这些小鼠中，lacZ取代腱生蛋白表达（佐贺等人：《基因与发育》6:1821 - 1831，1992）。通过原位杂交以及使用几种针对小鼠TN-C的多克隆和单克隆抗体进行免疫细胞化学检测，发现在mRNA和蛋白质水平上，突变小鼠中TN-C的检测水平均低于野生型动物。TN-C免疫反应性在冠状切片中的分布异常，因为在体感皮层第4层的桶状野边界在大多数细胞体（可能还包括神经元）内无法通过细胞内检测到。对出生后早期动物脑组织匀浆的蛋白质印迹分析显示，突变动物中与TN-C免疫反应的蛋白带呈现异常模式，而β-半乳糖苷酶以预期分子量迁移，未掺入与TN-C的融合蛋白中，这表明剪接机制受到干扰。如尼氏染色所示，在突变小鼠中未检测到桶状野模式的明显紊乱。我们的观察结果表明，设计用于完全破坏TN-C表达的突变小鼠表现出可检测到的异常TN-C表达。
