Chemical and physical nature of active chromatin in SRS-lymphoma mouse lymphocyte

Chromatin was extracted from SRS-lymphoma and normal mouse lymphocyte by Chiu^s method. Their chromatin nuclear acid had not much difference, but the values of NHCP/HP and RNS/DNA in mouse SRS-lymphoma cells were higher than those in normal lymphocyte. These results showed that the NHCP increased significantly with tumor development; The ratio of DNase I limited digestion of chromatin in SES-lymphoma mouse cells were higher than that in normal mouse lyphocyte. The results showed that chromatin of SRS-lymphoma mouse cells contained more CNase I hypersensitive sites than normal mouse lymphocyte; The amount of protein released chromatin from SRS-lympnoma mouse cells were higher than that from normal mouse lymphocyte during DNase I digestion. The results showed that the NHCP specifically binded active chromatin was closely related to the increasing of active sites and transcriptional activity of chromatin; The thermal denatuation curve showed that the hyperchromic effect of SRS-lymphoma chromatin was higher than that of normal lymphocyte, the result suggested that the chromatin structure was much loose in SRS-lymphoma cells.