TRANSPOSITION OF DNASE HYPERSENSITIVE CHROMATIN TO THE NUCLEAR PERIPHERY COINCIDES TEMPORALLY WITH NERVE GROWTH FACTOR-INDUCED UP-REGULATION OF GENE-EXPRESSION IN PC12 CELLS

To test the hypothesis that the nonrandom organization of the contents of interphase nuclei represents a compartmentalization of function, w e examined the relative, spatial relationship of small nuclear ribonuc leoproteins (snRNPs) and of DNase I hypersensitive chromatin (DHC) in rat pheochromocytoma cells. In controls, DHC and snRNPs colocalized as pan-nuclear speckles. During nerve growth factor-induced differentiat ion, both snRNPs and DHC migrated to the nuclear periphery with the mi gration of DHC preceding that of snRNPs, resulting in their transient separation. The formation of DHC shells temporally coincided with an u p-regulation of neurofilament light chain mRNA. This indicates,that th e expression of this sequence may be associated with its spatial trans position to the nuclear periphery.