We have isolated the human α-catenin gene (CTNNAl), which encodes a cadherin-associated protein, and have determined its primary structure and chromosomal localization. The transcript of CTNNAl is 3.4 kb long and consists of 16 coding exons encoding 906 amino acids and at least one 5’ noncoding exon. The 102-kDa predicted protein is the same size as the murine homolog, and the amino acid sequences of the two proteins are 99.2% homologous. Analysis by reverse transcription-PCR revealed that this gene is expressed ubiquitously in normal tissues. It was mapped to chromosome band 5q31 by fluorescent in situ hybridizati