Differential roles of two types of Glycans for cell attachment and entry of Merkel cell polyomavirus

默克尔细胞多瘤病毒（MCPyV）是默克尔细胞癌（MCC）的病原体（Feng et al.，2008; Shuda等人，2008年）。虽然在其他多瘤病毒中，初始附着（并且有时进入）由细胞表面上的唾液酸化糖缀合物介导，但MCPyV需要硫酸化糖胺聚糖（GAG）用于附着，并且需要唾液酸（Sia）和硫酸化GAG两者用于培养细胞的有效转导（Neu et al. 2012; Schowalter等人，2011年）。在这里，我们的目标是在分子水平上破译这些不同类型的聚糖对MCPyV附着和进入所起的作用。将结合结构生物学技术（蛋白质晶体学、NMR光谱学和天然质谱法）、基于细胞的感染测定和序列定义的糖低聚体来阐明MCPyV感染早期步骤的分子机制。由于糖胺聚糖是一种大而天然的异质生物分子，该项目需要内部生产化学均质的寡糖，用于结构生物学实验和功能研究。因此，我们的目标包括GAG领域的方法学发展，这些方法学发展也适用于需要GAG进行感染的其他病毒的研究。

Merkel cell polyomavirus (MCPyV) is a causative agent of Merkel cell carcinoma (MCC) (Feng et al., 2008; Shuda et al., 2008). While in other polyomaviruses initial attachment (and sometimes entry) is mediated by sialylated glycoconjugates on the cells surface, MCPyV requires sulfated glycosaminoglycans (GAGs) for attachment and both sialic acid (Sia) and sulfated GAGs for efficient transduction of cultured cells (Neu et al., 2012; Schowalter et al., 2011). Here, we aim to decipher, on the molecular level, the individual roles that these different types of glycans play for MCPyV attachment and entry. Structural biology techniques (protein crystallography, NMR spectroscopy, and native mass spectrometry), cell-based infection assays, and sequence-defined glycooligomers will be combined to elucidate the molecular mechanisms that underlie the early steps of MCPyV infection. Because GAGs are large and naturally heterogeneous biomolecules, the project requires in-house production of chemically homogeneous oligosaccharides for structural biology experiments and functional studies. Our objectives therefore include methodological developments in the field of GAGs that will also be applicable to the study of other viruses that require GAGs for infection.