Sequence, gene structure, and expression pattern of CTNNBL1, a minor-class intron-containing gene -: evidence for a role in apoptosis

We have identified and characterized a cDNA designated CTNNBLI (catenin (cadherin-associated protein), beta-like 1) coding for a protein of 563 amino acids having predicted structural homology to beta-catenin and other armadillo (arm) family proteins. CTNNBLI is expressed in multiple human tissues, and its sequence is conserved across widely divergent species. The human CTNNBLI gene on chromosome 20q11.2 contains 16 exons spanning > 178 kb. Intron 4 is a minor-class intron bearing AT at the 5' splice site and AC at the 3' splice site. An acidic domain, as well as a putative bipartite nuclear localization signal, a nuclear export signal, a leucine-isoleucine zipper, and phosphorylation motifs are present in the protein sequence. Transient expression of CTNNBLI in CHO cells results in localization to the nucleus and apoptosis. The rate of cell death was higher when cells were transfected with a carboxy-terminal fragment of CTNNBLI, suggesting that the apoptosis-inducing activity is a function of this region. (C) 2003 Elsevier Science (USA). All rights reserved.