Localization of spectrin in mammalian brain.

Spectrin is a major skeletal component of the erythrocyte membrane and is essential in controlling cell shape and structural stability. The brain has also been found to be rich in an immunoreactive and structural analogue of spectrin. In the present study, spectrin was localized in the mouse brain by indirect immunofluorescence using an antibody to erythrocyte spectrin that cross-reacts specifically with the alpha and beta subunits of brain spectrin. Spectrin antigens were concentrated in neuronal perikarya and cell processes. Synaptic structures and axons were observed to have little detectable spectrin antigen by immunofluorescence methodology. The cell bodies of glia had a less intense immunoreactivity in contrast to neurons, and glial processes and myelin were unstained. Cell nuclei of neural cells were not fluorescent. These results show that (a) spectrin is found in all regions of mammalian brain and its intensity corresponds to neural cell density, (b) different neural cell types contain variable spectrin content, and (c) within a single neural cell, the regional disposition of spectrin varies.