Tikoo K, Ali Z
Department of Biochemistry, Banaras Hindu University, Varanasi, India.
Biochem J. 1997 Feb 15;322 ( Pt 1)(Pt 1):281-7. doi: 10.1042/bj3220281.
Covalent modifications of histones in active and bulk chromatin fractions were studied in liver tissue from control and hypothyroid rats. The levels of acetylation and ubiquitination of histones were similar in the active and bulk chromatin fractions, and were not influenced by hypothyroidism. Histone H2A only was phosphorylated in control active and bulk chromatin fractions. The extent of this phosphorylation did not differ between the two fractions, but hypothyroidism greatly suppressed it. Indicating an association with tissue growth. ADP-ribosylation of histones was found to be mainly associated with transcriptional inactivation of the chromatin, while histone methylation was correlated with growth inhibition of the tissue, as observed with hypothyroidism. The validity of these conclusions will, however, depend upon the similarity of the turnover rates of these covalent modifications between active and inactive chromatin and between control and hypothyroid states.
在对照大鼠和甲状腺功能减退大鼠的肝脏组织中，研究了活性染色质组分和整体染色质组分中组蛋白的共价修饰。活性染色质组分和整体染色质组分中组蛋白的乙酰化和泛素化水平相似，且不受甲状腺功能减退的影响。仅组蛋白H2A在对照活性染色质组分和整体染色质组分中发生磷酸化。这种磷酸化的程度在两个组分之间没有差异，但甲状腺功能减退极大地抑制了它。表明与组织生长有关。发现组蛋白的ADP核糖基化主要与染色质的转录失活相关，而组蛋白甲基化与组织生长抑制相关，如甲状腺功能减退时所观察到的。然而，这些结论的有效性将取决于这些共价修饰在活性染色质和非活性染色质之间以及对照状态和甲状腺功能减退状态之间的周转率的相似性。
