斑马鱼Z-OTU蛋白在卵子发生和胚胎发育早期的表达(英文)
Identification of Z-OTU protein during zebrafish oogenesis and early embryogenesis
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摘要: 斑马鱼z-otu基因编码的蛋白可能具有DUBs活性, 它包含OTU和TUDOR结构域, 属于OTU相关蛋白酶家族的成员。该研究将原核表达的融合蛋白(OTU结构域和GST)纯化后免疫新西兰兔, 获得多克隆抗体anti-Z-OTU, 并利用该抗体对Z-OTU蛋白质在斑马鱼卵子发生和早期胚胎发育过程中的表达进行了分析。根据原位和整体免疫组织化学检测结果并结合以前的研究结论, 分析并比较了z-otu基因的mRNA和蛋白质的分布, 发现在卵子发生和早期胚胎发育过程中, z-otu基因的mRNA和蛋白质表达模式存在明显差异:mRNA仅在卵子发生早期表达, 卵母细胞受精后才重新开始表达, 而其蛋白在卵子发生过程中均表达; 在卵子发生过程中, mRNA分布于细胞质中, 而蛋白质先分布于细胞核中, 然后向细胞质迁移, 接着又向卵母细胞生发泡(germinal vesicle, GV)集中。推测Z-OTU蛋白类似于其他具有去泛素化酶活性的OTU相关蛋白酶, 对于卵母细胞减数分裂过程中生发泡破裂、生发泡迁移及维持胚胎的分裂是必需的。Abstract: Zebrafish (Danio rerio) Z-OTU, containing OTU and TUDOR domains, was predicted to be a member of OTU-related protease, a family of the deubiquitylating enzymes (DUBs). A previous report from our laboratory clearly describes the expression patterns of z-otu mRNA. Here, we characterized the Z-OTU protein during zebrafish oogenesis and early embryogenesis. After prokaryotic expression, the recombinant protein of the OTU domain and GST was purified and injected into rabbits to obtain the polyclonal antibody-anti-Z-OTU, which was used for immunohistochemistry in zebrafish ovaries and embryos. Interestingly, obvious differences existed between the expression patterns of z-otu mRNA and its protein during oogenesis and early embryogenesis. In stage I oocytes, z-otu mRNA was detected in cytoplasm while its protein existed in the germinal vesicle. In addition, its protein was distributed during entire oogenesis, while mRNA was not detected in oocytes at stage IV or mature oocytes. The z-otu mRNA disappeared after midblastula transition (MBT) and its protein gradually decreased after this stage. We inferred that Z-OTU protein, like other OTU-related protease with DUB activity, was required for germinal vesicle breakdown of oocytes during meiosis, germinal vesicle migration, and embryo cleavage maintenance.