Chaurasia P, Thakur M K
Biochemistry & Molecular Biology Laboratory, Banaras Hindu University, Varanasi, India.
Mol Biol Rep. 1998 Jan;25(1):63-9. doi: 10.1023/a:1006835732729.
The positioning of nucleosomes has been analysed by comparing the pattern of cutting sites of a probing reagent on chromatin and naked DNA. For this purpose, high molecular weight DNA and nuclei from the liver of young (18 +/- 2 weeks) and old (100 +/- 5 weeks) Wistar male rats were digested with micrococcal nuclease (MNase) and hybridized with 32P-labelled rat satellite DNA probe. A comparison of the ladder generated by MNase with chromatin and nuclei indicates long range organization of the satellite chromatin fiber with distinct non-random positioning of nucleosomes. However, the positioning of nucleosomes on satellite DNA does not vary with age. For studying the periodicity and subunit structure of satellite DNA, high molecular weight DNA from the liver of young and old rats were digested with different restriction enzymes. Surprisingly, no noteworthy age-related change is visible in the periodicity and subunit structural organization of the satellite DNA. These results suggest that the nucleosome positioning and the periodicity of liver satellite DNA do not vary with age.
通过比较探测试剂在染色质和裸露DNA上的切割位点模式，对核小体的定位进行了分析。为此，用微球菌核酸酶（MNase）消化来自年轻（18±2周）和年老（100±5周）Wistar雄性大鼠肝脏的高分子量DNA和细胞核，并用32P标记的大鼠卫星DNA探针进行杂交。将MNase与染色质和细胞核产生的梯状条带进行比较，表明卫星染色质纤维具有长程组织，核小体具有明显的非随机定位。然而，卫星DNA上核小体的定位并不随年龄变化。为了研究卫星DNA的周期性和亚基结构，用不同的限制性内切酶消化年轻和年老大鼠肝脏的高分子量DNA。令人惊讶的是，卫星DNA的周期性和亚基结构组织中没有明显的与年龄相关的变化。这些结果表明，肝脏卫星DNA的核小体定位和周期性不随年龄变化。
