Characterisation of two highly conserved but non-allelic cellular disintegrins from rabbit testis

Two novel cellular disintegrin genes (termed ADAM 6d and ADAM 6e: Gen Bank accession numbers U82750 and U82751) were isolated and characterised from a rabbit testicular cDNA library. The cDNAs have open reading frames encoding for proteins of 731 and 730 amino acids, respectively. They share an amino-acid homology of greater than 89% and a nucleotide base matching of 94% in both the coding and non-coding regions. PCR of DNA extracted from both the parents and progeny of wild rabbits was used to demonstrate that the genes are non-allelic. Recombinant ADAM 6e fused to maltose binding protein was prepared and polyclonal antibodies produced in mice. These polyclonal antibodies recognised two bands with molecular masses of 42 kDa and 46 kDa on Western blots of rabbit sperm extracts run on SDS PAGE reducing gels. The implications of the presence of these two highly conserved proteins in rabbit testis and on sperm are discussed.