O-linked β-N-acetylglucosamine (O-GlcNAc) is a single sugar modification found on many different classes of nuclear and cytoplasmic proteins. Addition of this modification, by the enzyme O-linked N-acetylglucosamine transferase (OGT), is dynamic and inducible. One major class of proteins modified by O-GlcNAc is transcription factors. O-GlcNAc regulates transcription factor properties through a variety of different mechanisms including localization, stability and transcriptional activation. Maintenance of embryonic stem (ES) cell pluripotency requires tight regulation of several key transcription factors, many of which are modified by O-GlcNAc. Octamer-binding protein 4 (Oct4) is one of the key transcription factors required for pluripotency of ES cells and more recently, the generation of induced pluripotent stem (iPS) cells. The action of Oct4 is modulated by the addition of several post-translational modifications, including O-GlcNAc. Previous studies in mice found a single site of O-GlcNAc addition responsible for transcriptional regulation. This study was designed to determine if this mechanism is conserved in humans. We mapped 10 novel sites of O-GlcNAc attachment on human Oct4, and confirmed a role for OGT in transcriptional activation of Oct4 at a site distinct from that found in mouse that allows distinction between different Oct4 target promoters. Additionally, we uncovered a potential new role for OGT that does not include its catalytic function. These results confirm that human Oct4 activity is being regulated by OGT by a mechanism that is distinct from mouse Oct4.

中文翻译：

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O-GlcNAc转移酶调节人Oct4的转录活性

O-连接的β -N乙酰氨基葡萄糖（O-GlcNAc的）是单糖修饰在许多不同的类核和细胞质蛋白的发现。通过O-连接的N酶加成这种修饰-乙酰氨基葡萄糖转移酶（OGT）是动态的且可诱导的。被O-GlcNAc修饰的一类主要蛋白质是转录因子。O-GlcNAc通过多种不同的机制调节转录因子的特性，包括定位，稳定性和转录激活。维持胚胎干（ES）细胞多能性需要严格调节几个关键的转录因子，其中许多因子都被O-GlcNAc修饰。八聚体结合蛋白4（Oct4）是ES细胞多能性所必需的关键转录因子之一，最近，它是诱导性多能干（iPS）细胞的产生。通过添加几个翻译后修饰（包括O-GlcNAc）来调节Oct4的作用。先前在小鼠中的研究发现，O-GlcNAc添加的单个位点负责转录调控。本研究旨在确定该机制在人类中是否保守。我们绘制了人类Oct4上O-GlcNAc附着的10个新位点，并确认了OGT在Oct4转录激活中的作用，该位点不同于在小鼠中发现的位点，从而可以区分不同的Oct4目标启动子。此外，我们发现了不包含其催化功能的OGT潜在的新作用。这些结果证实了人Oct4的活性是由OGT通过不同于小鼠Oct4的机制进行调节的。并确认了OGT在Oct4转录激活中的作用与小鼠中发现的不同，该位置允许区分不同的Oct4目标启动子。此外，我们发现了不包含其催化功能的OGT潜在的新作用。这些结果证实了人Oct4的活性是由OGT通过不同于小鼠Oct4的机制进行调节的。并确认了OGT在Oct4转录激活中的作用与小鼠中发现的不同，该位置允许区分不同的Oct4目标启动子。此外，我们发现了不包含其催化功能的OGT潜在的新作用。这些结果证实了人Oct4的活性是由OGT通过不同于小鼠Oct4的机制进行调节的。