Adhesive interactions between neurons and astroglia are likely to play an important role during central nervous system development. Using a monoclonal antibody (designated MAb 1A1) raised against purified neonatal rat astrocytes, I have characterized some of the in vitro functional and biochemical properties of a potentially novel cell surface molecule. By indirect immunofluorescence, the antibody labels subpopulations of astrocytes (flat type-1 astrocytes and Bergmann glia) and cells derived from the mesenchyme (leptomeninges and fibroblasts). The latter showed 1A1$ sp{+}$ immunoreactivity only when grown to confluency. Cell-cell contact and extracellular matrix molecules were found to play a role in the regulation of 1A1 antigen expression on leptomeninges. 1A1 Fab fragments inhibited the binding of neuron to astrocyte and astrocyte to astrocyte, but not of neuron to neuron in an in vitro adhesion assay, thus indicating that this surface antigen may function as a cell adhesion molecule on astrocytes. Addition of Fab fragments of MAb 1A1 also reduced leptomeningeal cell adhesion. Further functional antibody perturbation experiments indicated that this surface molecule mediates neurite outgrowth on astrocytes and neuronal migration on Bergmann glia via a heterophilic-binding mechanism. Both immunoprecipitation and immunocytochemical analysis showed the timing of 1A1 antigen expression in postnatal rat cerebellum to coincide with the developmental period of granule cell migration along Bergmann glia. On SDS-PAGE, the immunopurified 1A1 surface molecule migrated as a single molecular weight band of $ approx$135 kd and appeared to be poorly glycosylated. Based on its unique cell-type distribution, functional properties and biochemical analysis, this 135 kd glycoprotein is likely to be distinct from other known cell adhesion molecules expressed on astrocytes.
| Identifer | oai:union.ndltd.org:LACETR/oai:collectionscanada.gc.ca:QMM.41718 |
| Date | January 1994 |
| Creators | Mittal, Bina |
| Contributors | David, S. (advisor) |
| Publisher | McGill University |
| Source Sets | Library and Archives Canada ETDs Repository / Centre d'archives des thèses électroniques de Bibliothèque et Archives Canada |
| Language | English |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Format | application/pdf |
| Coverage | Doctor of Philosophy (Department of Neurology and Neurosurgery.) |
| Rights | All items in eScholarship@McGill are protected by copyright with all rights reserved unless otherwise indicated. |
| Relation | alephsysno: 001397688, proquestno: NN94686, Theses scanned by UMI/ProQuest. |
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