Genomic structure, chromosome mapping and expression analysis of the humanAXIN2 gene

Conductin is a Wnt signalling protein and serves as a negative regulator of beta -catenin stability. We have previously isolated the human homolog (AX IN2) of the murine conductin gene and shown that it is mutated in colorecta l cancer (CRC) with defective mismatch repair (MMR). Here we report the det ailed genomic structure of this gene by analysis of cDNA and genomic clones . The gene spans greater than or equal to 25 kb containing ten exons rangin g from 96 bp to 904 bp. All splice donor and acceptor sites conform to the GT/AG rule. FISH (Fluorescence in situ Hybridization) analysis localized th is gene to human chromosome band 17q24 and showed that it exists as a singl e copy in the human genome. Northern blot analysis from different human org ans demonstrated that the AXIN2 gene is highly expressed in human thymus, p rostate. testis, small intestine and ovarian tissues but expressed at a low er level in colon. The data reported here provides a framework for further analysis of this important Writ signalling protein in vertebrate developmen t and tumorigenesis. Copyright (C) 2001 S. Karger AG, Basel.