Chaurasia P, Mukherjee S, Thakur M K
Biochemistry & Molecular Biology Laboratory, Banaras Hindu University, Varanasi, India.
Biochem Mol Biol Int. 1996 Dec;40(6):1261-70. doi: 10.1080/15216549600201913.
EcoRI digestion of nuclei and their subsequent lysis with EDTA solubilizes 45% and 36% of chromatin DNA from the liver of young (18 +/- 2 weeks) and old (100 +/- 5 weeks) rats, respectively. After hybridization with 185 bp rat satellite I DNA, these soluble fractions are found to be enriched in specific DNA sequences such as satellite DNA. Besides regular repeat pattern, a major portion of the satellite chromatin forms higher order organization. Digestion kinetics confirms condensation of satellite DNA-containing chromatin similar to that of bulk chromatin in old age. Furthermore, densitometric scanning of the slot-blot of soluble chromatin fractions reveals loss of satellite DNA in the old. However, an increase in the linker histone H1 and its subfraction H1zero in the satellite DNA-enriched fraction of chromatin from old rats suggests greater compaction. These results provide the first evidence that the satellite DNA-containing chromatin differs in the liver of young and old rats.
用EcoRI消化细胞核，随后用EDTA裂解，分别可使幼年（18±2周）和老年（100±5周）大鼠肝脏中45%和36%的染色质DNA溶解。与185 bp大鼠卫星I DNA杂交后，发现这些可溶性部分富含特定的DNA序列，如卫星DNA。除了规则的重复模式外，大部分卫星染色质形成更高层次的结构。消化动力学证实，含卫星DNA的染色质的凝聚与老年时的整体染色质相似。此外，对可溶性染色质部分的狭缝印迹进行光密度扫描发现，老年大鼠中卫星DNA减少。然而，老年大鼠染色质中富含卫星DNA的部分中连接组蛋白H1及其亚组分H1zero增加，表明其压缩程度更高。这些结果首次证明，幼年和老年大鼠肝脏中含卫星DNA的染色质存在差异。
