Annunziato A T, Seale R L
Biochemistry. 1982 Oct 26;21(22):5431-8. doi: 10.1021/bi00265a008.
The DNA of newly replicated chromatin is comprised of two components, distinguishable by their solubility characteristics and requirements for maturation. One of these components possesses core histones, typical nucleosomal structure, a nuclease-resistant core containing 146 base pairs (bp) of new DNA, and all the nucleosomal species found in bulk chromatin (due to bound histone H1 and high mobility group proteins). In addition, this class of nascent chromatin exhibits a shortened repeat length of approximately 165 bp, as opposed to the 288-bp repeat of bulk chromatin. Within 10 min of DNA synthesis, the spacing of mature chromatin is established; the spacing maturation can occur in the absence of protein synthesis. The second class of nascent DNA is distinguished from the nucleosomal component by its insolubility, lack of discernible nucleosomal organization, and dependence on protein synthesis to attain typical subunit structure. This unassembled component is not free DNA, as demonstrated by its intermediate resistance to nucleolytic degradation. The structural properties and maturation requirements of this material suggest that it is the site of de novo nucleosome assembly.
新复制染色质的DNA由两个成分组成，可根据它们的溶解性特征和成熟所需条件加以区分。其中一个成分含有核心组蛋白、典型的核小体结构、一个对核酸酶有抗性的核心，该核心包含146个碱基对（bp）的新DNA，以及在整体染色质中发现的所有核小体种类（由于结合了组蛋白H1和高迁移率族蛋白）。此外，这类新生染色质的重复长度缩短至约165 bp，而整体染色质的重复长度为288 bp。在DNA合成的10分钟内，成熟染色质的间距得以确立；间距成熟可在没有蛋白质合成的情况下发生。第二类新生DNA的特点是不溶、缺乏可辨别的核小体组织，且依赖蛋白质合成来获得典型的亚基结构，以此与核小体成分相区分。这种未组装的成分不是游离DNA，对核酸降解的中等抗性证明了这一点。这种物质的结构特性和成熟所需条件表明它是从头组装核小体的位点。
