Loss ofHindIII cleavage sites in theD-amino acid oxidase gene in some inbred strains of mice.

D-Amino acid oxidase cDNA was amplified by a polymerase chain reaction using RNA extracted from the mouse kidney. When digested withHindIII, the cDNAs of the BALB/c and ddY/DAO(-) mice were cleaved into two fragments whereas the cDNA of the ddY/DAO(+) mice was not. Sequencing revealed that nucleotide-471 of the cDNAs was G in the BALB/c and ddY/DAO(-) mice whereas it was substituted for C in the ddY/DAO(+) mice. This base substitution was the cause of the failure of the cleavage of the cDNA of the ddY/DAO(+) mice.Examination of other strains of inbred mice showed thatD-amino-acid oxidase cDNAs of A/J, AKR, C57BL/6, CD-1, CF#1, ICR, DBA/2, NZB and NZW mice were cleaved withHindIII into two fragments whereas those of C3H/He, CBA/J and NC mice were not. Genomic DNAs extracted from the mice of these 15 strains were digested withHindIII and hybridized withD-amino-acid oxidase cDNA. A 18.2-kb fragment hybridized with the probe in the C3H/He, CBA/J, ddY/DAO(+) and NC mice whereas two fragments of 12 kb and 6.2 kb hybridized in the other mice. These results are consistent with those of the cDNAs, confirming the loss of theHindIII cleavage site in the C3H/He, CBA/J, ddY/DAO(+) and NC mice. The Southern hybridization revealed a loss of a differentHindIII cleavage site in the A/J, AKR, C57BL/6, DBA/2, ICR and NZB mice.The substitution at nucleotide-471 should cause a substitution of an amino acid residue. However, this substitution did not affect catalytic activity ofD-amino acid oxidase.