Histone H4 acetylation in plant heterochromatin is altered during the cell cycle
Histone H4 acetylation in plant heterochromatin is altered during the cell cycle
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DOI：
10.1007/s004120050239
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发表时间：
1997-08-01
期刊：
影响因子：
1.6
通讯作者：
Schubert, I
中科院分区：
文献类型：
--
作者：
Belyaev, ND;Houben, A;Schubert, I
使用多克隆抗体针对乙酰化亚型的组蛋白H4（H4乙酰化赖氨酸位置5，8，12，16和H4四乙酰化），间接免疫荧光显示超乙酰化的所有H4变种在核仁组织者区（NOR）的中期染色体的蚕豆。转录活性和后期复制异染色质区域被证明是hypoacetylated赖氨酸位置5，8和12。其余染色质显示平均荧光。这些模式被改变时，去乙酰化酶被封闭的根尖分生组织暴露于阿司他丁A超过2小时前固定。在这些条件下，所有的赖氨酸位置，除了赖氨酸8，似乎是超乙酰化的NOR，此外在突出的异染色质结构域。这一观察结果代表了细胞周期中组蛋白乙酰化模式的一个迄今为止独特的开关。这显然是由乙酰化的H4.Ac5、12和16的沉积或复制后直接乙酰化引起的，随后在细胞进入有丝分裂前被脱乙酰酶还原（H4.Ac16）或甚至逆转（H4.Ac5和12）。
Using polyclonal antibodies directed against acetylated isoforms of histone H4 (H4 acetylated at lysine positions 5, 8, 12, 16 and H4 tetraacetylated), indirect immunofluorescence revealed hyperacetylation for all H4 variants at the nucleolus organizer region (NOR) of metaphase chromosomes of the field bean Vicia faba. The transcriptionally inactive and late-replicating heterochromatin regions proved to be hypoacetylated at lysine positions 5, 8 and 12. The remaining chromatin showed average fluorescence. These patterns were altered when deacetylase was blocked by exposure of root tip meristems to trichostatin A for more than 2 h prior to fixation. Under these conditions, all lysine positions, except lysine 8, appeared to be hyperacetylated at the NOR and in addition at the prominent heterochromatin domains. This observation represents a hitherto unique switch of histone acetylation pattern during the cell cycle. This is apparently caused by deposition of acetylated H4.Ac5, 12 and 16 or by acetylation directly after replication, which later on becomes reduced (H4.Ac16) or even reversed (H4.Ac5 and 12) by deacetylase before cells enter mitosis.