Developmental changes in DNAse I digestibility and RNA template activity of neuronal nuclei relative to the postnatal appearance of a short DNA repeat length.

Neurons of the rat cerebral hemispheres are known to undergo a postnatal shift to a short DNA repeat length. In the present study we report that rat neuronal nuclei are more sensitive to digestion with DNAse I when isolated at a developmental stage after the shift in neuronal DNA repeated length compared to nuclei isolated before the shift. This observation may suggest that a decondensation of neuronal chromatin accompanies the postnatal shift in DNA repeat length. We have also found that neuronal nuclei isolated after the shift to a short DNA repeat length demonstrate an increased ability to synthesize RNA in vitro.