Reiteration frequency of delta-crystallin DNA in lens and non-lens tissues of chick embryos. delta-Crystallin gene is not amplified during lens cell differentiation.

The differentiation of embryonic chick lens fibers is characterized by an increased rate of synthesis of the lens protein, delta-crystallin, and accumulation of delta-crystallin mRNA. In the present study, the number of delta-crystallin genes in lens and non-lens tissues of embryonic chicks has been determined to test whether the accumulation of delta-crystallin mRNA during lens fiber differentiation is associated with an amplification of delta-crystallin genes. DNA from embryonic chick lens fibers, embryonic chick lens epithelia, or whole chick embryos with the eyes removed, was annealed with [3H]DNA complementary to delta-crystallin mRNA. Analysis of the annealing reactions indicated that the sequences for delta-crystallin are in the unique fraction of the chick genome, and are not amplified in the lens during embryonic development.