Involvement of cadherins 7 and 20 in mouse embryogenesis and melanocyte transformation.

We have determined the expression profiles of cdh7, and the related cdh20 during development. Both transcripts are found in the adult brain, but only cadherin-20 mRNA was detected during embryogenesis. In mouse embryos, cadherin-20 is synthesized by the forebrain, anterior neural ridge, developing visual system, primitive external granular layer of the cerebellum and a subset of neural crest cells likely to develop into melanoblasts. We found that the other embryonic tissues in which cadherin-20 was synthesized depended on genetic background. Melanoma cell lines contained transcripts for cadherin-7 but not for cadherin-20. The majority of the malignant melanoma cell lines produced N-cadherin (N-Cad) and/or cadherin-7 whereas melanocyte cell lines did not. The converse was observed for E-cadherin (E-Cad). Our data suggest that during development cadherin-20 is a key player in compartmentalization of the neural tube and establishment of neural circuitry. Finally, during oncogenesis, cadherin-7, N-cad and E-cad could be used as an efficient marker set for melanoma.