Histone exchange activity and its correlation with histone acetylation status in porcine oocytes
Histone exchange activity and its correlation with histone acetylation status in porcine oocytes
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DOI：
10.1530/rep-10-0164
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发表时间：
2011-04-01
期刊：
影响因子：
3.8
通讯作者：
Naito, Kunihiko
中科院分区：
文献类型：
--
作者：
Endo, Tsutomu;Imai, Aoi;Naito, Kunihiko
在哺乳动物卵母细胞中，染色质中的组蛋白 H3 和组蛋白 H4 (H4) 在生发囊泡 (GV) 阶段高度乙酰化，并在 GV 分解 (GVBD) 后全面脱乙酰化。尽管体细胞中核核心组蛋白可以被胞质游离组蛋白交换，但哺乳动物卵母细胞中是否也是如此仍不清楚。在本研究中，我们检测了 GVBD 前后成熟猪卵母细胞的组蛋白交换活性，并研究了该活性与 H4 N 末端尾部乙酰化谱和染色质中整体组蛋白乙酰化水平之间的相关性。我们将Flag标记的H4（H4-Flag）mRNA注射到GV卵母细胞中，发现Flag信号定位于染色质。接下来，我们注射了突变的 H4-Flag 的 mRNA，该突变缺乏所有乙酰化位点和整个 N 末端尾部，并发现 H4 N 末端尾部及其修饰对于组蛋白掺入染色质来说不是必需的。尽管缺乏乙酰化位点，突变的 H4-Flag mRNA 注射并没有降低染色质上的乙酰化水平，表明组蛋白交换部分发生在 GV 染色质中。与GV卵母细胞相反，将H4-Flag蛋白注射到第二次减数分裂中期卵母细胞后，在染色质上未检测到Flag信号。这些结果表明，猪卵母细胞减数分裂成熟期间组蛋白交换活性发生变化，并且 H4 N 末端尾部的乙酰化谱对组蛋白掺入染色质没有影响，并且不影响其中组蛋白乙酰化的整体水平。复制（2011）141 397-405
In mammalian oocytes, histone H3 and histone H4 (H4) in the chromatin are highly acetylated at the germinal vesicle (GV) stage, and become globally deacetylated after GV breakdown (GVBD). Although nuclear core histones can be exchanged by cytoplasmic free histones in somatic cells, it remains unknown whether this is also the case in mammalian oocytes. In this study, we examined the histone exchange activity in maturing porcine oocytes before and after GVBD, and investigated the correlations between this activity and both the acetylation profile of the H4 N-terminal tail and the global histone acetylation level in the chromatin. We injected Flag-tagged H4 (H4-Flag) mRNA into GV oocytes, and found that the Flag signal was localized to the chromatin. We next injected mRNAs of mutated H4-Flag, which lack all acetylation sites and the whole N-terminal tail, and found that the H4 N-terminal tail and its modification were not necessary for histone incorporation into chromatin. Despite the lack of acetylation sites, the mutated H4-Flag mRNA injection did not decrease the acetylation level on the chromatin, indicating that the histone exchange occurs partially in the GV chromatin. In contrast to GV oocytes, the Flag signal was not detected on the chromatin after the injection of H4-Flag protein into the second meiotic metaphase oocytes. These results suggest that histone exchange activity changes during meiotic maturation in porcine oocytes, and that the acetylation profile of the H4 N-terminal tail has no effect on histone incorporation into chromatin and does not affect the global level of histone acetylation in it. Reproduction (2011) 141 397-405