DETECTION OF TENASCIN-C IN THE NERVOUS-SYSTEM OF THE TENASCIN-C MUTANT MOUSE

We have investigated the expression of tenascin-C (TN-C) in the somato sensory cortex of early postnatal mutant mice in which lacZ was report ed 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 a t levels lower in the mutant than in wild type animals by in situ hybr idization and by immunocytochemistry using several poly- and monoclona l antibodies directed against mouse TN-C. The distribution of TN-C imm unoreactivity in coronal sections was abnormal in that the barrel fiel d boundaries in layer 4 of the somatosensory cortex could not be detec ted in the mutant mice. Furthermore, TN-C was detected intracellularly in most cell bodies, including possibly also neurons. Western blot an alysis of homogenates of brain tissue from early postnatal animals sho wed an abnormal pattern of protein bands immunoreactive for TN-C in mu tant animals while beta-galactosidase migrated at its expected molecul ar weight without incorporation into fusion proteins with TN-C, sugges ting disturbed splicing mechanisms. No gross disturbances in the patte rning of barrel fields could be detected in the mutant mice as shown b y Nissl staining. Our observations show that the mutant mouse designed to be nully disrupted for TN-C expression shows detectable and abnorm al TN-C expression. (C) 1995 Wiley-Liss, Inc.