The tenascin-C knockout revisited

In the past seven Sears, two groups have independently produced tenascin-C- knockout mice. These mice are born alive and, originally, were described as showing no abnormalities. More recent studies, many involving pathological intervention, have shown that tenascin-C-knockout mice have several defect s. The mice exhibit abnormal behaviour, as well as abnormalities in brain c hemistry. They also show defects in structure and repair of neuromuscular j unctions, in the ability to recover from snake-venom-induced glomerulonephr itis and in chemically induced dermatitis, Healing of skin wounds is morpho logically normal, but the mice exhibit defects in healing after suture inju ry of corneas, In both skin and corneal wounds, fibronectin expression is a bnormally low in tenascin-C-knockout mice. Finally, in vitro studies indica te that haemopoietic activity is defective in bone marrow from these mice, When examined together, these studies provide evidence for precise function s for tenascin-C, as well as an explanation for why the sequence of tenasci n-C is so highly phylogenetically conserved.