Purification of Nuclei and Fractionation of Chromatin From rat Liver and Electrophoresis of Non-Histone Chromatin Proteins by two Dimensional Gel Electrophoresis

Nuclei were prepared from adult rat liver by a slightly modified ultracentrifugation method,with a yield of about 5%.The quality of rat liver nuclei has been ascertained by observations with the phase contract microscope,electron microscope,transcriptional activity and estimations of enzyme activity.The chromatin of rat liver was fractionated by the method of hydroxyapatite (HAP) chromatography.The U.V.spectrum of each fraction was obtained individually.The chemical compositions of the nuclei,chromatin,Up (a group of nonhistone proteins binding DNA loosly),deUpgchromatin and each fraction from HAP were determined.NP (a group of nonhistone proteins binding DNA tightly) were extracted from deUP-chromatin with phenol.UP and NP were analysed by two dimensional gel electrophoresis.