Dishevelled 1 (DVL1), DVL2 and DVL3 are DIX-domain proteins implicated in the WNT signaling pathway. Here, we searched for a novel DIX-domain protein by using bioinformatics. Uncharacterized human KIAA1735 gene was found encoding a novel DIX-domain protein. Mouse ortholog of human KIAA1735 gene was next identified, and the nucleotide sequence of mouse Kiaa1735 cDNA was determined in silico by assembling nucleotide sequences of ESTs BY753211, BQ931084, CA750490, BQ960056 and a 5'-truncated partial cDNA AK082960. Human KIAA1735 protein (472 aa) and mouse Kiaa1735 protein (474 aa) showed 90.9% total-amino-acid identity. Myosine-tail homologous (MTH) domain and C-terminal DIX domain were conserved between human KIAA1735 and mouse Kiaa1735 proteins. A tyrosine phosphorylation site (Tyr 242) within the MTH domain was conserved between human KIAA1735 and mouse Kiaa1735 proteins. Leucine zipper motif (codon 202-237) and another tyrosine phosphorylation site (Tyr 272) were identified within the MTH domain of human KIAA1735, but not within that of mouse Kiaa1735. Human KIAA1735 mRNA was expressed in brain, subchondral bone, and also in lung cancer. KIAA1735 gene, consisting of 16 exons, was about 45 kb in size. KIAA1735 gene was linked to DLAT gene in tail-to-head manner with an interval less than 4.0 kb. KIAA1735 gene on human chromosome 11q23.1 was located between D11S1391 and D11S1347 loci, the region deleted in sporadic breast cancer. This is the first report on comprehensive characterization of the KIAA1735 gene.