FIGURE 2.

Isolated nuclei swell with changes of divalent salts. (A) Isolated nuclei attached by polylysine to a coverslip show dilation and recovery of the nucleus prelabeled with YO-PRO, with a heterogeneous label. (B) Nuclei free in solution swell to 170% of their original projected area with the chelation of salt from the media with EDTA. Adding back divalent salt returns nuclei to their original size. (C) The projected area of native isolated nuclei (▪) increases linearly with the addition of EDTA (□). Conversely, nuclei isolated into media with no salt (•) shrink linearly with addition of concentrated salts (○). DNase increases the projected area of both swollen and unswollen nuclei, indicating that the chromatin network contributes to regulation of nuclear size.