组蛋白 H2B 单泛素化 (H2Bub1) 是一种动态翻译后修饰，与 DNA 损伤相关，在多种转录调控程序中发挥着关键作用。癌细胞表现出多种表观遗传变化，特别是任何异常的 H2Bub1 经常与肿瘤的发展相关。然而，我们对组蛋白 H2B 去泛素化的机制及其在干细胞分化过程中的相关功能的理解仍然只有部分了解。在这项研究中，我们希望研究干细胞分化过程中去泛素化酶 (DUB) 对 H2Bub1 调节的作用。在寻找 H2B 单泛素化的潜在 DUB 过程中，我们发现了 Usp7，一种泛素特异性蛋白酶，在小鼠胚胎癌细胞的神经元分化过程中充当 H2B 泛素化的负调节因子。在视黄酸介导的细胞分化过程中，CRISPR/Cas9 系统导致 Usp7 基因功能丧失，从而导致 H2Bub1 的增加。此外，Usp7基因的敲除特别提高了神经元分化相关基因的表达，包括星形细胞特异性标记物和少突胶质细胞特异性标记物。特别是，神经胶质谱系细胞特异性转录因子（包括少突胶质细胞转录因子 2、胶质纤维酸性蛋白和 SRY-box 转录因子 10）在神经元分化过程中显着上调。因此，我们的研究结果表明 Usp7 在小鼠胚胎癌细胞的胶质生成中具有新的作用。

Histone H2B monoubiquitination (H2Bub1) is a dynamic posttranslational modification which are linked to DNA damage and plays a key role in a wide variety of regulatory transcriptional programs. Cancer cells exhibit a variety of epigenetic changes, particularly any aberrant H2Bub1 has frequently been associated with the development of tumors. Nevertheless, our understanding of the mechanisms governing the histone H2B deubiquitination and their associated functions during stem cell differentiation remain only partially understood. In this study, we wished to investigate the role of deubiquitinating enzymes (DUBs) on H2Bub1 regulation during stem cell differentiation. In a search for potential DUBs for H2B monoubiquitination, we identified Usp7, a ubiquitin-specific protease that acts as a negative regulator of H2B ubiquitination during the neuronal differentiation of mouse embryonic carcinoma cells. Loss of function of the Usp7 gene by a CRISPR/Cas9 system during retinoic acid-mediated cell differentiation contributes to the increase in H2Bub1. Furthermore, knockout of the Usp7 gene particularly elevated the expression of neuronal differentiation related genes including astryocyte-specific markers and oligodendrocyte-specific markers. In particular, glial lineage cell-specific transcription factors including oligodendrocyte transcription factor 2, glial fibrillary acidic protein, and SRY-box transcription factor 10 was significantly upregulated during neuronal differentiation. Thus, our findings suggest a novel role of Usp7 in gliogenesis in mouse embryonic carcinoma cells.