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：1981
卷号：78
期号：11
页码：6803-6807
DOI：10.1073/pnas.78.11.6803
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：Switches of the types of histones synthesized and incorporated into chromatin occur during sea urchin embryogenesis. In an attempt to define the possible effects of these variant histones on chromatin structure, I have isolated and characterized nucleosome core particles from Strongylocentrotus purpuratus blastula (nearly 100% early histones) and pluteus (75% late histones). Both particles contain 146-base-pair lengths of DNA wrapped around an octamer of H2A, H2B, H3, and H4. Although sharing these similarities with the canonical core particle, the nucleosome structures have certain features that differ from those of typical adult tissues. Both the reversible and the irreversible conformational transitions occurring on heating core particles are destabilized in the embryonic particles vs. "typical" core particles. The blastula core particle unfolds more easily than pluteus (or other) nucleosomes under the stress of low ionic strength. The rate of DNase I digestion of pluteus core particles is about half that of particles from blastula; certain cutting sites differ in their susceptibility between the two embryonic particles and between these two and the canonical core particle. The data demonstrate that the variant histones synthesized during early embryogenesis have demonstrable effects on chromatin structure, even at this basic level.
