O-linked N-acetylglucosaminyltransferase inhibition prevents G2/M transition in Xenopus laevis oocytes
O-linked N-acetylglucosaminyltransferase inhibition prevents G2/M transition in Xenopus laevis oocytes
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DOI：
10.1074/jbc.m700444200
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发表时间：
2007-04-27
影响因子：
4.8
通讯作者：
Bodart, Jean-Francois
中科院分区：
文献类型：
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作者：
Dehennaut, Vanessa;Lefebvre, Tony;Bodart, Jean-Francois
完全发育的非洲爪蟾卵母细胞在第一次减数分裂的前期被阻滞在G（2）样状态。减数分裂的恢复也被称为G（2）/M转换。这一事件的特征是生发泡破裂（GVBD）和磷酸化水平的爆发，反映了M期促进因子（MPF）和MAPK途径的激活。除了磷酸化和泛素化途径外，越来越多的证据表明细胞溶质和细胞核特异性O-GlcNAc糖基化也有助于细胞周期调节。为了研究O-GlcNAc与细胞周期的关系，使用了非洲爪蟾卵母细胞，其中大多数M期调节剂已经被发现。O-GlcNAc转移酶抑制剂Alloxan以浓度依赖性方式阻断G（2）/M转换。四氧嘧啶防止GVBD和MPF和MAPK激活，无论是由孕酮或卵细胞质注射触发。解毒酶（SOD和过氧化氢酶）的加入并没有拯救GVBD，表明四氧嘧啶的效果并没有发生通过活性氧的生产。这些结果通过使用苯并恶唑啉酮衍生物（XI）（一种新的O-GlcNAc转移酶抑制剂）得到加强。相反，注射O-（2-乙酰氨基-2-脱氧-D-吡喃葡萄糖基亚基）氨基-N-苯基氨基甲酸酯（一种O-GlcNAcase抑制剂）加速了成熟过程。谷氨酰胺：6-磷酸果糖酰胺转移酶抑制剂重氮丝氨酸和6-重氮-5-氧代正亮氨酸未能预防GVBD。这样的策略似乎是低效的;事实上，成熟和未成熟卵母细胞中的UDP-GlcNAc测定揭示了核苷酸糖的恒定池。最后，我们观察到，细胞周期蛋白B2，MPF调节亚基，与一个未知的O-GlcNAc合作伙伴。目前的工作强调了O-GlcNAc在G（2）/M转换中的关键作用，并强烈表明其功能是细胞周期调控所必需的。
Full-grown Xenopus oocytes are arrested at the prophase of the first meiotic division in a G(2)-like state. Progesterone triggers meiotic resumption also called the G(2)/M transition. This event is characterized by germinal vesicle breakdown ( GVBD) and by a burst in phosphorylation level that reflects activation of M-phase-promoting factor ( MPF) and MAPK pathways. Besides phosphorylation and ubiquitin pathways, increasing evidence has suggested that the cytosolic and nucleus-specific O-GlcNAc glycosylation also contributes to cell cycle regulation. To investigate the relationship between O-GlcNAc and cell cycle, Xenopus oocyte, in which most of the M-phase regulators have been discovered, was used. Alloxan, an O-GlcNAc transferase inhibitor, blocked G(2)/M transition in a concentration-dependent manner. Alloxan prevented GVBD and both MPF and MAPK activations, either triggered by progesterone or by egg cytoplasm injection. The addition of detoxifying enzymes ( SOD and catalase) did not rescue GVBD, indicating that the alloxan effect did not occur through reactive oxygen species production. These results were strengthened by the use of a benzoxazolinone derivative ( XI), a new O-GlcNAc transferase inhibitor. Conversely, injection of O-(2-acetamido-2-deoxy-D-glucopyranosylidene) amino-N-phenylcarbamate, an O-GlcNAcase inhibitor, accelerated the maturation process. Glutamine: fructose-6-phosphate amidotransferase inhibitors, azaserine and 6-diazo-5-ox-onorleucine, failed to prevent GVBD. Such a strategy appeared to be inefficient; indeed, UDP-GlcNAc assays in mature and immature oocytes revealed a constant pool of the nucleotide sugar. Finally, we observed that cyclin B2, the MPF regulatory subunit, was associated with an unknown O-GlcNAc partner. The present work underlines a crucial role for O-GlcNAc in G(2)/M transition and strongly suggests that its function is required for cell cycle regulation.