期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1983
卷号：80
期号：3
页码：815-819
DOI：10.1073/pnas.80.3.815
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：We have investigated the DNase I sensitivity of transcriptionally active DNA sequences in intact nuclei and isolated chromatin from embryos of wheat (Triticum aestivum L.). Nuclei or isolated chromatin was incubated with DNase I, and the extent of DNA digestion was monitored as percentage acid solubility. The resistant DNA and DNA from sham-digested controls were used to drive reassociation reactions with cDNA populations corresponding to either total poly(A)+RNA from unimbibed wheat embryos or polysomal poly(A)+RNA from embryos that had imbibed for 3 hr. Sequences complementary to either probe were depleted in DNase I-resistant DNA from nuclei and from chromatin isolated under low-ionic-strength conditions. This indicates that transcriptionally active sequences are preferentially DNase I sensitive in plants. In chromatin isolated at higher ionic strength, cDNA complementary sequences were not preferentially depleted by DNase I treatment. Therefore, the chromatin structure that confers preferential DNase I sensitivity to transcriptionally active genes appears to be lost when the higher-ionic-strength method of preparation is used. Treatment of wheat nuclei with DNase I causes the release of four prominent nonhistone chromosomal proteins that comigrate with wheat high mobility group proteins on NaDodSO4 gels.
