THE CHICKEN LYSOZYME GENE 5'-MAR AND THE DROSOPHILA HISTONE SAR ARE ELECTROELUTABLE FROM ENCAPSULATED AND DIGESTED NUCLEI

Cultured chicken cells were encapsulated in agarose microbeads, lysed in a near-physiological buffer and resulting encapsulated nuclei were digested with a restriction enzyme and electroeluted. After removal of similar to 97% of the chromatin, the nuclear lamina, residual nucleol i and an internal nuclear network remained. The majority of nascent RN A was also recovered in digested and electroeluted nuclei. Surprisingl y, however, the chicken lysozyme gene 5' MAR was quantitatively electr oeluted from digested nuclei of expressing and non-expressing cells, a s well as the promoter region and the coding sequence. When encapsulat ed nuclei were digested partially, the proportion of elutable 5' MAR c hromatin was comparable to that of elutable bulk chromatin. Furthermor e, after digestion of encapsulated nuclei from Drosophila Kc cells, th e histone SAR was electroeluted to the same extent as bulk chromatin. We conclude that the lysozyme gene 5' MAR and the histone SAR are not permanently attached to a nuclear matrix or scaffold.