Novel use of bovine zeta-crystallin as a conformational DNA probe to characterize a phase transition zone and terminally differentiating fiber cells in the adult canine ocular lens

Using a novel immunocytochemical staining method, we aimed to characterize the phase transition zone (PTZ) (similar to 100 mum) in adult ocular lenses and the process of terminal differentiation (denucleation) within normal f iber cells. The binding to DNA of zeta-(xi) crystallin (Z-DNA-binding prote in) and anti-double-stranded (ds-)-B-DNA antibody probes was found to decli ne gradually throughout denucleating fibers, with a precipitous decrease oc curring at about 100 mum (PTZ). Nuclei of superficial fiber cells (in front of the PTZ) showed the highest DNA probe-binding values, followed by middl e fibers (MF) and deep fibers (DF). With the use of xi -crystallin, anti-ds -B-DNA antibody, and anti-single stranded (ss-) DNA antibody probes, it was possible to reveal a loss of reactivity of fiber cell ds-DNA. Ss-DNA antib ody binding was seen initially in the MF and reached its highest intensity level in the DF. The pattern of xi -crystallin probe-DNA reactivity correla tes with the loss of anti-B-DNA antibody staining and decreased eosin-prote in staining. These data suggest that a reorganization of DNA and intracellu lar protein supramolecular order in normal adult lenses occurs at a depth o f about 100 mum (PTZ).