Selective digestion of transcriptionally active ovalbumin genes from oviduct nuclei.

Publisher Website
Google Scholar
Abstract
Analysis of the DNA of isolated nucleosomes suggests that virtually all genomic DNA sequences are organized in this basid chromatin subunit. Although histones reside on the transcriptionally active ovalbumin genes in the oviduct, the organization of proteins about this gene renders it highly sensitive to deoxyribonuclease I(deoxyribonucleate 5''-oligonucleotidohydrolase, EC 3.1.4.5). Treatment of oviduct nuclei from the laying hen with pancreatic deoxyribonuclease I results in the preferential digestion of over 70% of the ovalbumin sequences when only 10% of the total nuclear DNA was solubilized. Treatment of liver nuclei does not reveal selective sensitivity of these genes to DNase I. Furthermore, regions of DNA not actively transcribed, such as the endogenous leukosis virus genes in the oviduct, are not selectively degraded by this enzyme. Similar digestions with micrococcal nuclease, however, reveal no specific digestion of transcriptionally active chromatin. This is an aspect of structure that may be necessary to permit transcription of the chromatin complex.