Differential expression of alpha-E-catenin and alpha-N-catenin in the developing cerebral cortex.

Alpha (alpha) catenin proteins can regulate both cell adhesion and cell proliferation. Here, we characterize the expression of two forms of alpha-catenin, alphaE-catenin and alphaN-catenin, in the developing cerebral cortex and primary cortical cultures. In situ hybridization and immunofluorescence studies reveal that alphaE-catenin is highly expressed in neuroepithelial precursor cells in the developing cortical ventricular zone, with markedly reduced expression in the cortical plate; in contrast, alphaN-catenin expression is low in the ventricular zone and high in the developing cortical plate. In the ventricular zone, immunoreactivity for both alphaE-catenin and alphaN-catenin is enriched in rings at the lumenal surface, reflecting localization at adherens junctions together with beta-catenin. Expression of alphaE-catenin in primary cortical precursor cultures is initially robust, but declines as neural precursors differentiate into neurons. Reflecting its expression pattern in vivo, alphaN-catenin is expressed in both neural precursors as well in neurons differentiated in culture. These differential expression patterns of alphaE-catenin and alphaN-catenin suggest both distinct and overlapping functions during cortical development.