组蛋白乙酰化转移酶KAT8对小鼠卵泡发育影响酌研究

发布时间：2018-01-19 12:24

本文关键词： Kat8 H4K16ac 卵母细胞卵泡生育力活性氧　出处：《中国科学技术大学》2017年博士论文　论文类型：学位论文

【摘要】：卵泡发育的正常进行对于雌性生育能力的维持十分重要。卵泡发育是一个复杂的生物学过程,其间涉及到细胞的生长、增殖及分化等方面,需要基因的精确调控。组蛋白乙酰化是一种重要的基因调控方式,乙酰化转移酶和去乙酰化酶能够通过改变组蛋白与DNA的结合能力改变染色质的状态,进而对基因的转录进行调控。赖氨酸(K)乙酰化转移酶KAT8,作为果蝇中X染色体剂量补偿系统中的重要组成部分,负责组蛋白H4第十六位赖氨酸大部分的乙酰化。我们发现Kat8在小鼠卵母细胞及颗粒细胞中均有所表达,并且高表达于生发泡期卵母细胞胞核。接下来我们进一步利用条件性敲除小鼠模型研究了Kat8在小鼠卵泡发育过程中的功能,结果表明卵母细胞特异敲除Kat8后小鼠不育,次级及腔前卵泡的发育受阻,闭锁卵泡数目增多,大量卵母细胞出现严重的DNA损伤和凋亡,而颗粒细胞的增殖并未受到明显影响。Kat8敲除的卵母细胞组蛋白H4第十六位赖氨酸乙酰化的水平显著下调,细胞内异染色质的形态明显异常,卵母细胞中抗氧化基因Prdx1、Prdx2、Gpx1及Gpx4的表达显著下调,活性氧水平明显升高。向敲除小鼠注射抗氧化剂N-乙酰半胱氨酸可以促进敲除鼠的卵子发生和卵泡发育,同时降低卵母细胞活性氧、DNA损伤及凋亡水平。KAT8可以直接结合在抗氧化基因的启动子区域,调控这些基因表达。而颗粒细胞敲除Kat8对小鼠的生育力及卵泡发育并无明显影响。综上所述,我们的研究结果表明卵母细胞内KAT8通过调控细胞内抗氧化基因的表达降低了卵母细胞的活性氧水平,进而减少了卵母细胞的凋亡,提高了卵泡的存活能力,维持了雌性的正常生育力。KAT8是迄今为止首个报道的在小鼠卵泡发育过程中所必需的乙酰化转移酶,同时本研究为卵泡发育障碍引起的不孕症的诊断、治疗提供了重要的科学依据。
[Abstract]:The normal development of follicles is very important for the maintenance of female fertility. Follicular development is a complex biological process, which involves cell growth, proliferation and differentiation. Histone acetylation is an important gene regulation. Acetyltransferase and deacetylase can change the chromatin state by changing the binding ability of histone to DNA. Lysine K) acetyltransferase KAT8 is an important part of the dose compensation system of X chromosome in Drosophila. Responsible for most of the acetylation of lysine at histone H4 16th. We found that Kat8 was expressed in mouse oocytes and granulosa cells. And high expression in the blastocyst oocyte nucleus. Then we further use the conditional knockout mouse model to study the function of Kat8 in the development of mouse follicles. The results showed that after specific knockout of oocytes in Kat8 mice, the development of secondary and preantral follicles was blocked, the number of atresia follicles increased, and a large number of oocytes showed severe DNA damage and apoptosis. However, the proliferation of granulosa cells was not significantly affected by. Kat8 knockout oocyte histone H4 16th site lysine acetylation level was significantly down-regulated, and the morphology of heterochromatin was significantly abnormal. The expression of antioxidation gene Prdx1, Prdx2, Gpx1 and Gpx4 was significantly down-regulated in oocytes. The level of reactive oxygen species (Ros) was significantly increased. The injection of N- acetylcysteine into knockout mice could promote oogenesis and follicle development in knockout mice and decrease reactive oxygen species (Ros) in oocytes at the same time. The level of DNA damage and apoptosis. KAT8 can directly bind to the promoter region of antioxidant gene. Regulation of these genes expression. Granulosa cell knockout Kat8 has no significant effect on the fertility and follicular development of mice. Our results suggest that KAT8 in oocytes can reduce reactive oxygen species (Ros) levels in oocytes by regulating the expression of antioxidant genes in oocytes and thus reduce the apoptosis of oocytes. KAT8 is the first reported acetyltransferase necessary in mouse follicular development. At the same time, this study provides an important scientific basis for the diagnosis and treatment of infertility caused by follicular dysplasia.
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2017
【分类号】：Q492.5

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