Laboratory of Animal Embryonic Biotechnology, College of Animal Science and Technology, China Agricultural University, Beijing, People's Republic of China.
Theriogenology. 2011 Mar 1;75(4):638-46. doi: 10.1016/j.theriogenology.2010.09.031. Epub 2010 Nov 12.
Deterioration in the quality of mammalian mature oocytes during metaphase-II (M-II) arrest is called "oocyte aging". Although histone acetylation may affect the progression of aging in murine oocytes, the mechanism is unknown. The objective was to determine the role of ooplasmic reactive oxygen species (ROS) in acetylation of histone H4 at lysine 12 (acH4K12) in porcine aged oocytes in vitro. Based on immunostaining with a specific antibody, acetylation of H4K12 in porcine oocytes increased during in vitro aging, which coincided with changing patterns of ooplasmic ROS content. Furthermore, both hydrogen peroxide (H(2)O(2)), and the mitochondrial membrane potential disrupter, carbonyl cyanide 3-chlorophenylhydrazone (CCCP), which can moderately elevate oocyte ROS content, significantly increased acetylation levels of H4K12 in porcine oocytes. It was noteworthy that acetylation in the CCCP group was decreased when ROS was counteracted by cysteine, a common antioxidant. In addition, the intracellular mRNA abundance of acetyltransferase gene HAT1 in aged and H(2)O(2) treated oocytes was higher than in M-II phase oocytes, suggesting that HAT1 was involved in this reaction. After parthenogenetic activation, a lower proportion of oocytes developed to the blastocyst stage after CCCP or H(2)O(2) treatment when compared with M-II phase oocytes (20 and 0% for CCCP and H(2)O(2) groups, respectively, versus 42% for the M-II group, P < 0.05). In conclusion, elevated levels of H4K12 acetylation were attributed to increased ooplasmic ROS content during porcine oocyte aging in vitro.
哺乳动物成熟卵母细胞在中期 II 期（M-II）阻滞期间质量下降称为“卵母细胞衰老”。尽管组蛋白乙酰化可能会影响鼠卵母细胞衰老的进程，但机制尚不清楚。本研究旨在确定卵质活性氧（ROS）在体外猪老化卵母细胞中组蛋白 H4 赖氨酸 12 乙酰化（acH4K12）中的作用。通过特异性抗体免疫染色，发现猪卵母细胞在体外老化过程中 H4K12 的乙酰化增加，这与卵质 ROS 含量的变化模式一致。此外，过氧化氢（H2O2）和线粒体膜电位破坏剂 3-氯苯甲脒（CCCP），可以适度增加卵母细胞 ROS 含量，显著增加猪卵母细胞 H4K12 的乙酰化水平。值得注意的是，当 ROS 被半胱氨酸（一种常见的抗氧化剂）拮抗时，CCCP 组中的乙酰化降低。此外，在老化和 H2O2 处理的卵母细胞中，乙酰转移酶基因 HAT1 的细胞内 mRNA 丰度高于 M-II 期卵母细胞，表明 HAT1 参与了该反应。在孤雌激活后，与 M-II 期卵母细胞相比，CCCP 或 H2O2 处理后的卵母细胞发育为囊胚的比例较低（CCCP 和 H2O2 组分别为 20%和 0%，而 M-II 组为 42%，P<0.05）。总之，体外猪卵母细胞老化过程中卵质 ROS 含量增加导致 H4K12 乙酰化水平升高。
