Characterization of three novel human cadherin genes (CDH7, CDH19, and CDH20) clustered on chromosome 18q22-q23 and with high homology to chicken cadherin-7.

Full-length coding sequences of two novel human cadherin cDNAs were obtained by sequence analysis of several EST clones and 5' and 3' rapid amplification of cDNA ends (RACE) products. Exons for a third cDNA sequence were identified in a public-domain human genomic sequence, and the coding sequence was completed by 3' RACE. One of the sequences (CDH7L1, HGMW-approved gene symbol CDH7) is so similar to chicken cadherin-7 gene that we consider it to be the human orthologue. In contrast, the published partial sequence of human cadherin-7 is identical to our second cadherin sequence (CDH7L2), for which we propose CDH19 as the new name. The third sequence (CDH7L3, HGMW-approved gene symbol CDH20) is almost identical to the mouse "cadherin-7" cDNA. According to phylogenetic analysis, this mouse cadherin-7 and its here presented human homologue are most likely the orthologues of Xenopus F-cadherin. These novel human genes, CDH7, CDH19, and CDH20, are localized on chromosome 18q22-q23, distal of both the gene CDH2 (18q11) encoding N-cadherin and the locus of the six desmosomal cadherin genes (18q12). Based on genetic linkage maps, this genomic region is close to the region to which Paget's disease was linked. Interestingly, the expression patterns of these three closely related cadherins are strikingly different.