Metabolic labeling of glycans with clickable unnatural sugars has enabled glycan analysis in multicellular systems. However, cell-type-specific labeling of glycans in vivo remains challenging. Here we develop genetically encoded metabolic glycan labeling (GeMGL), a cell-type-specific strategy based on a bump-and-hole pair of an unnatural sugar and its matching engineered enzyme. N-pentynylacetylglucosamine (GlcNAl) serves as a bumped analog of N-acetylglucosamine (GlcNAc) that is specifically incorporated into glycans of cells expressing a UDP-GlcNAc pyrophosphorylase mutant, AGX2^F383G. GeMGL with the 1,3-di-O-propionylated GlcNAl (1,3-Pr₂GlcNAl) and AGX2^F383G pair was demonstrated in cell cocultures, and used for specific labeling of glycans in mouse xenograft tumors. By generating a transgenic mouse line with AGX2^F383G expressed under a cardiomyocyte-specific promoter, we performed specific imaging of cardiomyocyte glycans in the heart and identified 582 cardiomyocyte O-GlcNAcylated proteins with no interference from other cardiac cell types. GeMGL will facilitate cell-type-specific glycan imaging and glycoproteomics in various tissues and disease models.

用可点击的非天然糖对聚糖进行代谢标记使多细胞系统中的聚糖分析成为可能。然而，体内聚糖的细胞类型特异性标记仍然具有挑战性。在这里，我们开发了基因编码的代谢聚糖标记 (GeMGL)，这是一种基于非天然糖及其匹配工程酶的凹凸对的细胞类型特异性策略。N-戊炔基乙酰葡糖胺 (GlcNAl) 作为N-乙酰葡糖胺 (GlcNAc) 的突变类似物，专门掺入表达 UDP-GlcNAc 焦磷酸化酶突变体 AGX2 ^F383G的细胞的聚糖中。GeMGL 与 1,3-二-O-丙酰化 GlcNAl (1,3-Pr ₂ GlcNAl) 和 AGX2 ^F383G对在细胞共培养中得到证实，并用于小鼠异种移植肿瘤中聚糖的特异性标记。通过生成具有在心肌细胞特异性启动子下表达的 AGX2 F383G 的转基因小鼠系，我们对心脏中的心肌细胞聚糖进行了特异性成像，并鉴定了 582 个心肌细胞 O-GlcNAcylated 蛋白，且不受其他心肌细胞类型的^干扰。GeMGL 将促进各种组织和疾病模型中的细胞类型特异性聚糖成像和糖蛋白组学。