Cloning of the human homolog of conductin (AXIN2), a gene mapping to chromosome 17q23-q24.

Conductin or Axil, an Axin homolog, plays an important role in the regulation of beta-catenin stability in the Wnt signaling pathway. To facilitate the molecular analysis of the human gene, we isolated the human homolog, AXIN2. The cDNA contains a 2529-bp open reading frame and encodes a putative protein of 843 amino acids. Compared with rat and mouse homologs, AXIN2 shows an overall 89% amino acid identity. Several functional domains in this protein are highly conserved including the GRS (95.9%), GSK-3beta (96.3%), Dsh (98%), and beta-catenin (89.9%) domains. Radiation hybrid mapping localized the AXIN2 gene to human chromosome 17q23-q24, a region that shows frequent loss of heterozygosity in breast cancer, neuroblastoma, and other tumors. Human AXIN2 is thus a very strong candidate involved in multiple tumor types.