Factors affecting the heat-induced increase in protein content of chromatin.
Factors affecting the heat-induced increase in protein content of chromatin.
复制标题
影响热诱导染色质蛋白质含量增加的因素。
作者：
J. Roti;R. T. Winward
当HeLa细胞被加热（40至48/sup 0/C）时，观察到染色质蛋白质含量的时间和温度依赖性增加。如果将分离的细胞核在含7%小牛血清的培养基、100%小牛血清或细胞超声处理物的悬浮液中加热（45/sup 0/C，30 min），则未观察到染色质蛋白含量增加。当使用吐温80透化细胞时，染色质的蛋白质含量增加70%，而不需要热疗。这些结果表明，细胞结构是所需的热诱导的染色质蛋白质含量的增加发生，增加可以引起膜损伤。当细胞被加热（45/sup 0/C下15分钟）并返回到37/sup 0/C下的培养基中时，它们可以将染色质的蛋白质含量恢复到对照水平。因此，染色质蛋白质含量的恢复需要3小时。羟基脲（2 mM）、过量胸苷（3 mM）、放线菌素-D（5 mM）不抑制呼吸暂停。Mu.. g/ml）、Lucanthone（55. Mu.. g/ml）、2，4-二硝基苯酚（10 mM）、哇巴因（1 mM）或环己脲（50. Mu.. g/m.）。因此，主要的代谢过程是不需要恢复。然而，高（42/sup 0/C）和低（0/sup 0/C）温度抑制恢复过程。
When HeLa cells are heated (40 to 48/sup 0/C), a time- and temperature-dependent increase in the chromatin protein content is observed. If isolated nuclei are heated (45/sup 0/C, 30 min) in medium with 7% calf serum, in 100% calf serum, or in a suspension of cell sonicates, no increase in the chromatin protein content is observed. When cells are permeabilized using Tween 80, a 70% increase in the protein content of chromatin occurs without hyperthermia. These results suggest that cellular structure is required for the heat-induced increase in chromatin protein content to occur and that the increase can be caused by membrane damage. When cells are heated (15 min at 45/sup 0/C) and returned to medium at 37/sup 0/C, they can restore the protein content of chromatin to control levels. Thus restitution of the chromatin protein content requires 3 h. Restitution is not inhibited by hydroxyurea (2 mM), excess thymidine (3 mM), actinomycin-D (5 ..mu..g/ml), lucanthone (55 ..mu..g/ml), 2,4-dimitrophenol (10 mM), ouabain (1 mM), or cyclohexamide (50 ..mu..g/m.). Thus major metabolic processes are not required for restitution. However, high (42/sup 0/C) and low (0/sup 0/C) temperatures inhibit the restitution process.