A simple rapid method for isolation of nuclear lamina from Ehrlich ascites tumour cells using DNAse II

The method is based on the observation that digestion of detergent-treated rat liver nuclei with DNAse II in the presence of EDTA yelds empty shells devoid of internal network. Apart from its simplicity, the procedure proposed has some advantages over the existing methods for isolation of nuclear lamina. It is caried out under conditions which maintain the chromatin in a completely decondensed state. This avoids the selective effect of the local chromatin condensation (due to the presence of Mg in procedures employing DNAse I) on the composition of DNA population eventually associated with the lamina. The material after dissociation of histones in 2M NaCl containing the bulk of fragmented DNA is never exposed to solutions of low ionic strength. This avoids the formation of artifactual protein. The digestion and dehistonization are carried out in the presence of sucrose, known to inhibit protein aggregation. The method can be applied also to Guerin ascites tumour and rat liver using the procedure for isolation of structured chromatin