As an important posttranslational modification, ubiquitination plays an important role in regulating protein homeostasis in eukaryotic cells. In our previous studies, both the transcriptome and proteome suggested that ubiquitination is involved in the formation of chicken primordial germ cells (PGCs). Here, affinity enrichment combined with liquid chromatography–tandem mass spectrometry (MS/MS) was used to analyze the ubiquitome during the differentiation from embryonic stem cells to PGCs, and we identify that 724 lysine ubiquitinated sites were up-regulated in 558 proteins and 138 lysine ubiquitinated sites were down-regulated in 109 proteins. Furthermore, GO and KEGG enrichment analysis showed that ubiquitination regulates key proteins to participate in the progression of key events related to PGC formation and the transduction of key signals such as Wnt, MAPK, and insulin signals, followed by the detailed explanation of the specific regulatory mechanism of ubiquitination through the combined proteome and ubiquitome analysis. Moreover, both the activation and inhibition of neddylation were detrimental to the maintenance of the biological characteristics of PGCs, which also verified the importance of ubiquitination. In conclusion, this study provides a global view of the ubiquitome during the formation of PGCs by label-free quantitative ubiquitomics, which lays a theoretical foundation for the formation mechanism and specific application of chicken PGCs.

中文翻译：

---

泛素化在鸡原始生殖细胞的形成过程中起重要作用


泛素化作为一种重要的翻译后修饰，在调节真核细胞的蛋白质稳态中起着重要作用。在我们之前的研究中，转录组和蛋白质组都表明泛素化参与了鸡原始生殖细胞 （PGC） 的形成。在这里，亲和富集结合液相色谱-串联质谱 （MS/MS） 分析从胚胎干细胞分化为 PGC 过程中的泛素组，我们发现 724 个赖氨酸泛素化位点在 558 个蛋白质中上调，138 个赖氨酸泛素位点在 109 个蛋白质中下调。此外，GO 和 KEGG 富集分析表明，泛素化调节关键蛋白参与与 PGC 形成相关的关键事件的进展以及 Wnt、MAPK 和胰岛素信号等关键信号的转导，然后通过蛋白质组和泛素组分析详细解释泛素化的具体调控机制。此外，neddylation 的激活和抑制都不利于 PGCs 生物学特性的维持，这也验证了泛素化的重要性。综上所述，本研究通过无标记定量泛素组学提供了 PGCs 形成过程中泛素组学的全局视图，为鸡 PGCs 的形成机制和具体应用奠定了理论基础。