delta-catenin is a nervous system-specific adherens junction protein whichundergoes dynamic relocalization during development

delta-catenin is a member of the Armadillo repeat family and component of t he adherens junction discovered in a two-hybrid assay as a bona fide intera ctor with presenilin-1 (Zhou et al., [1997], NeuroReport 8:2085-2090), a pr otein which carries mutations that cause familial Alzheimer's disease. The expression pattern of delta-catenin was mapped between embryonic day 10 (E1 0) and adulthood by Northern blots, in situ hybridization and immunohistoch emistry in the mouse. In development, delta-catenin is dynamically regulate d with respect to its site of expression. It is first expressed within prol iferating neuronal progenitor cells of the neuroepithelium, becomes down-re gulated during neuronal migration, and is later reexpressed in the dendriti c compartment of postmitotic neurons. In the mouse, delta-catenin mRNA is e xpressed by E10, increases and peaks at postnatal day (P)7, with lower leve ls in adulthood. In the developing neocortex, delta-catenin mRNA is strongl y expressed in the proliferative ventricular zone and the developing cortic al plate, yet is conspicuously less prominent in the intermediate zone, whi ch contains migrating cortical neurons, delta-catenin protein forms a honey comb pattern in the neuroepithelium by labeling the cell periphery in a typ ical adherens junction pattern. By E18, delta-catenin expression shifts pri marily to nascent apical dendrites, a pattern that continues through adulth ood. The dynamic relocalization of delta-catenin expression during developm ent, taken together with previously published data which described a role f or delta-catenin in cell motility (Lu et al., [1999] J. Cell. Biol. 144:519 -532), suggests the hypothesis that delta-catenin regulation is closely lin ked to neuronal migration and may play a role in the establishment of matur e dendritic relationships in the neuropil. (C) 2000 Wiley-Liss, Inc.