MCD24 EXPRESSION IN THE DEVELOPING MOUSE-BRAIN AND IN ZONES OF SECONDARY NEUROGENESIS IN THE ADULT

Interactions mediated by cell surface glycoproteins are considered to be crucial during the formation of the nervous system. Using a monoclo nal antibody directed to mCD24, a glycosylphosphatidylinositol-anchore d membrane glycoprotein, we have mapped its distribution throughout th e mouse cerebral cortex during development and in young adult. Before birth, mCD24 immunoreactivity was observed in the intermediate zone, t he cortical plate and the marginal zone, whereas the ventricular zones were immunonegative. After birth, mCD24 expression declined rapidly i n the cortex, except in the corpus callosum (and other commissures in the brain) where immunoreactivity was still found until P20. Furthermo re, mCD24 expression was maintained in young adults (until P60, at lea st) in zones of secondary neurogenesis, such as the granule cells of t he dentate gyrus, the subventricular zone lining the anterior part of the lateral ventricles and a zone of cells extending between the stria tum and the corpus callosum to the centre of the olfactory bulb. In th is area mCD24 and polysialic acid neural cell adhesion molecule staini ngs were superimposed, and this corresponded to the pathway of migrati on of the olfactory immature neurons (subependymal layer). A layer of ciliated ependymal cells, lining all the ventricular walls, was also i mmunoreactive for mCD24. Thus, except for these epithelial-like cells, mCD24 was essentially found associated with differentiating compatibl e with a role for this glycoprotein in cell surface recognition and in signalling events occurring during neuronal migration and axonal grow th. Copyright (C) 1996 IBRO.