Alteration of higher order structure of rat liver chromatin by dietary composition.
Alteration of higher order structure of rat liver chromatin by dietary composition.
复制标题
饮食成分改变大鼠肝脏染色质高级结构。
DOI：
10.1093/jn/110.1.105
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发表时间：
1980
期刊：
影响因子：
--
通讯作者：
J. Sevall
中科院分区：
文献类型：
--
作者：
C. E. Castro;J. Sevall
用特异性酶探针微球菌核酸酶（EC 3.1.4.7）研究了饲养5 d的大鼠肝脏核染色质的高阶结构。微球菌核酸酶将真核染色质中50%的DNA消化成酸溶性核苷酸，而50%的DNA由于相关核蛋白而无法消化。这种DNA的选择性消化反应了普遍染色质亚基核小体的高级结构，核小体存在于低等真核生物、植物和动物中。当大鼠饲喂商业饲料时，肝染色质中50.3%的DNA被微球菌核酸酶消化。然而，当大鼠饲喂各种半合成饲料时，易受微球菌核酸酶消化的DNA数量随饲料的变化而变化（P < 0.0001）。对微球菌核酸酶敏感的DNA数量的差异从喂食高碳水化合物/无脂肪饮食的大鼠染色质的71.4%到喂食低碳水化合物/无蛋白质饮食的大鼠染色质的38.8%不等。用2.5%聚丙烯酰胺-0.5%琼脂糖凝胶电泳分析微球菌核酸酶酶切产生的DNA片段。喂食高碳水化合物/无脂肪饮食的大鼠的染色质被不含单体核小体的饮食更快地消化。据我们所知，这些饮食诱导的染色质高阶结构的改变是第一个通过体内调节发生的报道。
The higher order structure of rat liver chromatin from nuclei of animals fed stock or semi-synthetic diets for 5 days was investigated by a specific enzymatic probe, micrococcal nuclease (EC 3.1.4.7). Micrococcal nuclease digests 50% of DNA in eukaryotic chromatin into acid-soluble nucleotides while 50% of the DNA is resistant to digestion because of associated nucleoproteins. This selective digestion of DNA reflects higher orders of structure of the universal chromatin subunit, the nucleosome, found in lower eukaryotes, plants and animals. When rats were fed a commercial stock diet, 50.3% of the DNA in liver chromatin was digested by micrococcal nuclease. However, when rats were fed various semi-synthetic diets, the amount of DNA susceptible to micrococcal nuclease digestion varied as a function of diet (P less than 0.0001). Differences in the amount of DNA susceptible to micrococcal nuclease ranged from 71.4% for chromatin of rats fed a high carbohydrate/fat-free diet to 38.8% for chromatin of those fed a low carbohydrate/protein-free diet. DNA fragments generated by brief micrococcal nuclease digestion were analyzed by electrophoresis on 2.5% polyacrylamide--0.5% agarose gels. Chromatin from rats fed the high carbohydrate/fat-free diet was more rapidly digested to the monomer nucleosomin-free diet. To our knowledge, these diet-induced alterations in the higher order structure of chromatin are the first to be reported as occurring by in vivo modulation.