Role of UHRF1 in de novo DNA methylation in oocytes and maintenance methylation in preimplantation embryos.
Role of UHRF1 in de novo DNA methylation in oocytes and maintenance methylation in preimplantation embryos.
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DOI：
10.1371/journal.pgen.1007042
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发表时间：
2017-10
期刊：
影响因子：
4.5
通讯作者：
Sasaki H
中科院分区：
文献类型：
--
作者：
Maenohara S;Unoki M;Toh H;Ohishi H;Sharif J;Koseki H;Sasaki H
在配子体发生和着床前发育过程中，哺乳动物基因组CG位点的胞嘧啶甲基化是动态重编程的。先前的研究表明，卵母细胞衍生的DNMT1（一种维持性甲基转移酶）对于在着床前胚胎的印迹控制区维持和繁殖CG甲基化至关重要。在哺乳动物体细胞中，半甲基化CG结合蛋白UHRF1通过招募DNMT1到半甲基化CG位点，在维持CG甲基化中发挥关键作用。然而，UHRF1在卵子发生和着床前发育中的作用尚不清楚。在本研究中，我们发现UHRF1主要但不完全定位于卵母细胞和着床前胚胎的细胞质中。然而，较少数量的UHRF1存在于细胞核中，这与预期在DNA甲基化中的作用一致。然后，我们产生了卵母细胞特异性Uhrf1敲除（KO）小鼠，并发现，尽管卵发生本身不受影响，但来自KO卵母细胞的大部分胚胎在到达囊胚期之前死亡（母体效应）。亚硫酸氢盐全基因组测序显示，来自KO卵母细胞的囊胚的CG甲基化水平大大降低，这表明母体UHRF1对于维持着床前胚胎的CG甲基化至关重要，特别是在印迹控制区。令人惊讶的是，UHRF1也被发现在卵母细胞生长过程中促进新生CG和非CG甲基化：在UHRF1 KO卵母细胞中，转录非活性区域获得较少的甲基化，而转录活性区域，包括印迹控制区，不受影响或仅轻微影响。我们还发现，在卵母细胞生长的后期，从头甲基化是有缺陷的。据我们所知，这是第一个证明UHRF1在体内从头DNA甲基化中的作用的研究。我们的研究揭示了UHRF1在卵母细胞和早期胚胎的整体表观遗传重编程过程中的多种功能。哺乳动物基因组CG位点胞嘧啶甲基化是一种表观遗传修饰，对细胞分化和胚胎发育非常重要。在卵母细胞生长过程中，活跃转录区域获得CG和非CG甲基化。然而，受精后，除了某些基因控制区和一部分逆转录转座子保留CG甲基化外，这种甲基化在全局上被消除。我们通过产生卵母细胞特异性UHRF1基因敲除小鼠，研究了UHRF1在卵母细胞和着床前胚胎中的作用，UHRF1是维持体细胞、卵母细胞中CG甲基化所必需的蛋白质。我们发现卵母细胞来源的UHRF1蛋白对植入前胚胎中DNMT1（一种维持性DNA甲基转移酶）的核定位和CG维持性甲基化很重要，特别是在印迹控制区。出乎意料的是，我们发现卵母细胞中CG和非CG甲基化的增加也受到某些基因组区域Uhrf1敲除的影响。据我们所知，这是第一个证明UHRF1在体内从头DNA甲基化中的作用的研究。我们的研究揭示了UHRF1在卵母细胞和着床前胚胎的整体表观遗传重编程过程中的多种功能。
The methylation of cytosine at CG sites in the mammalian genome is dynamically reprogrammed during gametogenesis and preimplantation development. It was previously shown that oocyte-derived DNMT1 (a maintenance methyltransferase) is essential for maintaining and propagating CG methylation at imprinting control regions in preimplantation embryos. In mammalian somatic cells, hemimethylated-CG-binding protein UHRF1 plays a critical role in maintaining CG methylation by recruiting DNMT1 to hemimethylated CG sites. However, the role of UHRF1 in oogenesis and preimplantation development is unknown. In the present study, we show that UHRF1 is mainly, but not exclusively, localized in the cytoplasm of oocytes and preimplantation embryos. However, smaller amounts of UHRF1 existed in the nucleus, consistent with the expected role in DNA methylation. We then generated oocyte-specific Uhrf1 knockout (KO) mice and found that, although oogenesis was itself unaffected, a large proportion of the embryos derived from the KO oocytes died before reaching the blastocyst stage (a maternal effect). Whole genome bisulfite sequencing revealed that blastocysts derived from KO oocytes have a greatly reduced level of CG methylation, suggesting that maternal UHRF1 is essential for maintaining CG methylation, particularly at the imprinting control regions, in preimplantation embryos. Surprisingly, UHRF1 was also found to contribute to de novo CG and non-CG methylation during oocyte growth: in Uhrf1 KO oocytes, transcriptionally-inactive regions gained less methylation, while actively transcribed regions, including the imprinting control regions, were unaffected or only slightly affected. We also found that de novo methylation was defective during the late stage of oocyte growth. To the best of our knowledge, this is the first study to demonstrate the role of UHRF1 in de novo DNA methylation in vivo. Our study reveals multiple functions of UHRF1 during the global epigenetic reprogramming of oocytes and early embryos. The methylation of cytosine at CG sites in the mammalian genome is an epigenetic modification that is important for cell differentiation and embryonic development. During oocyte growth, the actively transcribed regions gain both CG and non-CG methylation. However, after fertilization, such methylation is globally erased, except for certain gene control regions and a subset of retrotransposons that retain CG methylation. We examined the role of UHRF1, a protein essential for the maintenance of CG methylation in somatic cells, in oocytes and preimplantation embryos by generating oocyte-specific Uhrf1 gene knockout mice. We found that oocyte-derived maternal UHRF1 protein was important for nuclear localization of DNMT1 (a maintenance DNA methyltransferase) and for CG maintenance methylation, particularly at the imprinting control regions, in preimplantation embryos. Unexpectedly, we found that the gain in CG and non-CG methylation in oocytes was also affected by Uhrf1 knockout in certain genomic regions. To the best of our knowledge, this is the first study to demonstrate a role of UHRF1 in de novo DNA methylation in vivo. Our study reveals multiple functions of UHRF1 during the global epigenetic reprogramming of oocytes and preimplantation embryos.
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DOI：
10.1126/science.1229277
发表时间：
2013-01-25
期刊：
Science (New York, N.Y.)
影响因子：
--
作者：
Hackett JA;Sengupta R;Zylicz JJ;Murakami K;Lee C;Down TA;Surani MA
通讯作者：
Surani MA
影响因子：
4.5
作者：
Kobayashi H;Sakurai T;Imai M;Takahashi N;Fukuda A;Yayoi O;Sato S;Nakabayashi K;Hata K;Sotomaru Y;Suzuki Y;Kono T
通讯作者：
Kono T
影响因子：
4
作者：
Delaval, K;Feil, R
通讯作者：
Feil, R
影响因子：
56.9
作者：
Bostick, Magnolia;Kim, Jong Kyong;Jacobsen, Steven E.
通讯作者：
Jacobsen, Steven E.
影响因子：
56.9
作者：
Bourc'his, D;Xu, GL;Bestor, TH
通讯作者：
Bestor, TH