Localization and expression of peptidylarginine deiminase 4 (PAD4) in mammalian oocytes and preimplantation embryos
Localization and expression of peptidylarginine deiminase 4 (PAD4) in mammalian oocytes and preimplantation embryos
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DOI：
10.1017/s0967199411000633
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发表时间：
2013-11-01
期刊：
影响因子：
1.7
通讯作者：
Miyake, Masashi
中科院分区：
文献类型：
--
作者：
Brahmajosyula, Manjula;Miyake, Masashi
翻译后修饰通常涉及在蛋白质残基上添加或去除各种官能团。然而，由肽基精氨酸脱亚胺酶 (PAD) 催化的瓜氨酸化涉及将一种氨基酸残基转化为另一种氨基酸残基。 PAD4 是五种亚型之一，是一种核酶，已知通过基因调控在发育、分化和细胞凋亡中发挥作用。为了研究 PAD4 在哺乳动物植入前胚胎发育中的可能作用，我们首先研究了 PAD4 和瓜氨酸蛋白在猪和小鼠卵母细胞以及孤雌生殖或体外受精 (IVF) 胚胎中的定位和表达。免疫荧光研究表明，PAD4 主要定位于猪卵母细胞和孤雌胚胎的细胞质中。然而，在 GV 破裂之前的晚期生发囊泡 (GV) 阶段卵母细胞中观察到 PAD4 的核转位，并且位于中期 (M)I 和 II 纺锤体周围。在囊胚中再次部分观察到核定位的 PAD4。在小鼠体外受精胚胎中，核易位从2细胞阶段开始，逐渐增加到囊胚期。 Western blot研究证实PAD4在猪的卵母细胞和孤雌胚胎中表达。在所研究胚胎的所有阶段的 GV、MI 和 MII 卵母细胞和细胞核的染色质上检测到颗粒形式的瓜氨酸蛋白。结果发现，瓜氨酸化的靶点是组蛋白（H3），而不是B23。因此，卵母细胞和胚胎中 PAD4 和瓜氨酸组蛋白 H3 的存在表明 PAD4 在植入前胚胎发育中可能发挥作用。
Post-translational modifications generally involve the addition or removal of various functional groups to or from the protein residues. However, citrullination, which is catalyzed by the peptidylarginine deiminases (PADs), involves conversion of one kind of amino acid residue into another. One of five isoforms, PAD4 is a nuclear enzyme known to play a role in development, differentiation and apoptosis through gene regulation. To investigate the possible role of PAD4 in mammalian preimplantation embryonic development, we first studied localization and expression of PAD4 and citrullinated proteins in pig and mouse oocytes, and parthenogenetic or in vitro fertilized (IVF) embryos. Immunofluorescence study revealed that PAD4 primarily localizes in the cytoplasm in pig oocytes and parthenogenetic embryos. However, the nuclear translocation of PAD4 was observed in late germinal vesicle (GV) stage oocytes prior to GV breakdown and was localized around the metaphase (M)I and II spindle. Nucleus localized PAD4 was noticed partially again in blastocysts. In mouse IVF embryos, nuclear translocation started from the 2-cell stage and gradually increased up to blastocyst. Western blot studies confirmed that PAD4 was expressed in oocytes, and parthenogenetic embryos of pig. Citrullinated proteins were detected in granular form on the chromatin in GV, MI and MII oocytes and nuclei in all the stages of the embryos studied. It was found that the target of citrullination was histone protein (H3), not B23. Therefore the presence of PAD4 and citrullinated histone H3 in oocytes and embryos suggested a possible role for PAD4 in preimplantation embryonic development.