DNA intercalators induce specific release of HMG 14, HMG 17 and other DNA-binding proteins from chicken erythrocyte chromatin.

Chicken erythrocyte nuclei were incubated with DNA intercalating agents in order to isolate from chromatin specific DNA-binding proteins whose binding specificity may be determined by DNA secondary and/or tertiary structure. The intercalating agents ethidium bromide (EtBr) and propidium iodide induce the specific release of high mobility group proteins HMG 14 and HMG 17 under low ionic strength conditions. Chloroquine (CQ) intercalation also results in the selective liberation of HMG 14 and HMG 17, but, in addition, selectively releases other nuclear proteins (including histone H1A) in a pH- and ionic strength-dependent fashion. The use of this new 'elutive intercalation' technique for the isolation and purification of 'sequence-specific' and 'helix-specific' DNA-binding proteins is suggested.