Use of the biotin-avidin system for labelling, isolation and characterization of neural cell-surface proteins.

We describe a method for the selective labelling, isolation and electrophoretic analysis of cell-surface molecules and extracellular matrix components. Intact tissues are reacted with activated esters of biotin and the labelled surface molecules identified on Western blots with horseradish-peroxidase-coupled or 35S-labelled streptavidin. Alternatively, the biotinylated proteins can be purified from tissue homogenates by affinity chromatography on an avidin-agarose column. Evidence is presented to show that this method is indeed specific for membrane and matrix components. Its practical application to embryonic neural tissues is demonstrated.