Somatic DNA recombination in a mouse genomic region, BC-1, in brain and non-brain tissue

The genomic region BC-1 (GenBank acc. No. AB075899) on mouse chromosome 16 has been reported as a genomic region undergoing somatic DNA recombination producing circular DNA and genomic deletion in brain during late embryogenesis. The present study shows that the BC-1 circular DNA production had already started on the 13th day of embryonic age, earlier than the previous observation that the circular DNA production started on the 15th through 17th embryonic day. The BC-1 deletion was also observed in the spleen and ocular lens. In situ hybridization analysis indicated that a human-homologous region in the BC-1 sequence was expressed in the lens at a perinatal period. These data suggest that the somatic DNA recombination in the BC-1 region is not restricted to brain tissue, and that the BC-1 DNA recombination relates to lens development.