A monoclonal antibody specific for alpha catenin, the 102 kD cadherin-associated protein, has been characterized and used to describe the expression and distribution pattern of alpha catenin in adult mice and mouse embryos. This monoclonal antibody recognized an epitope in the middle part of the a catenin molecule of various vertebrate species, and bound to neither vinculin nor alpha N catenin, which are cytoskeletal proteins with sequence similarity to alpha catenin. At the early mouse embryo stage (neurulae stage) alpha catenin was expressed and concentrated at cell-to-cell contact sites together with various types of cadherins in all tissues. In embryos al 12.5 days of gestation, the alpha catenin expression was gradually diminished selectively in central nervous tissues such as brain and spinal cord, and in most of the adult central nervous tissues the alpha catenin expression was hardly detected. In adult non-nervous tissues most of the cells examined expressed alpha catenin. Especially in well-polarized tissues such as epithelial cells, alpha catenin appeared to be highly concentrated at cell-to-cell adherens junctions where cadherins act as adhesion molecules. This loss of alpha catenin expression in central nervous tissues was observed not only in mice but also in other vertebrate species such as fish and newt, suggesting that this phenomenon has important implications from the view point of nervous tissue development.
