Pereira S L, Grayling R A, Lurz R, Reeve J N
Department of Microbiology, The Ohio State University, Columbus, OH 43210, USA.
Proc Natl Acad Sci U S A. 1997 Nov 11;94(23):12633-7. doi: 10.1073/pnas.94.23.12633.
Archaea contain histones that have primary sequences in common with eukaryal nucleosome core histones and a three-dimensional structure that is essentially only the histone fold. Here we report the results of experiments that document that archaeal histones compact DNA in vivo into structures similar to the structure formed by the histone (H3+H4)2 tetramer at the center of the eukaryal nucleosome. After formaldehyde cross-linking in vivo, these archaeal nucleosomes have been isolated from Methanobacterium thermoautotrophicum and Methanothermus fervidus, visualized by electron microscopy on plasmid and genomic DNAs, and shown by immunogold labeling, SDS/PAGE, and immunoblotting to contain archaeal histones, cross-linked into tetramers. Archaeal nucleosomes protect approximately 60 bp of DNA and multiples of approximately 60 bp from micrococcal nuclease digestion, and immunoprecipitation has demonstrated that most, but not all, M. fervidus genomic DNA sequences are associated in vivo with archaeal histones.
古细菌含有组蛋白，其一级序列与真核生物核小体核心组蛋白有共同之处，且三维结构本质上仅是组蛋白折叠结构。在此，我们报告了一些实验结果，这些实验证明古细菌组蛋白在体内将DNA压缩成与真核生物核小体中心由组蛋白(H3 + H4)2四聚体形成的结构相似的结构。在体内进行甲醛交联后，已从嗜热自养甲烷杆菌和嗜热栖热菌中分离出这些古细菌核小体，通过电子显微镜观察质粒和基因组DNA上的它们，并通过免疫金标记、SDS/聚丙烯酰胺凝胶电泳和免疫印迹表明其含有交联成四聚体的古细菌组蛋白。古细菌核小体保护约60 bp的DNA以及约60 bp的倍数不被微球菌核酸酶消化，免疫沉淀已证明，嗜热栖热菌的大多数（但不是全部）基因组DNA序列在体内与古细菌组蛋白相关联。
