A lamprey lens protein related to avian and reptilian delta crystallin

Delta crystallin has hitherto been considered specific to reptiles and birds. Evidence presented in this paper suggests that a major lens protein in adult river lampreys (Lampetra fluviatilis) is related to chick delta crystallin. Both are of similar size (Mr 45-50,000), and the lamprey protein cross-reacts with antibodies against chick delta crystallin in immunodiffusion, immunoelectrophoretic and immunoblotting tests. However, the charge properties and V8 proteolytic fragment patterns of the lamprey protein are markedly different from those of avian and reptilian delta crystallins. Preliminary evidence on the occurrence of delta-related DNA sequences in the genomes of all vertebrates examined, is also discussed.