岩藻糖基化是流感病毒受体糖链骨架的最常见修饰形式之一，可显著影响病毒在宿主细胞中的复制能力。项目前期研究已揭示H3N8和H1N1病毒结合岩藻糖基化唾液酸（SLeX）的分子机制，且证实鸡气管上皮细胞中有丰富的SLeX表达。SLeX的表达分布存在明显的物种和组织差异，其与H9N2病毒的亲和力可显著影响病毒在组织上的复制能力，暗示组织岩藻糖基化差异与病毒组织嗜性密切相关。为了回答岩藻糖基化在病毒组织嗜性中的作用和机制，本项目将以H9N2病毒为研究对象，通过糖芯片、质谱分析、CRISPR/Cas9、和分子动力学模拟等技术分析SLeX在鸡、鸭呼吸道及肠道组织的表达和分布，鉴定调控SLeX表达的关键岩藻糖转移酶基因，解析岩藻糖基化影响病毒组织嗜性的分子机制。项目成果将为岩藻糖基化受体与流感病毒的相互作用提供进一步认识，为构建禽流感病毒高产细胞系提供实验依据，也为其它以糖链为受体的病毒相关研究提供借鉴。

Fucosylation is one of the most common forms of modification of the sugar chain backbone of influenza virus sialic acids receptors, which can significantly affect the replication ability of virus in host cells. Our previous results have revealed the molecular mechanism of H1N1 influenza virus binding to Sialyl Lewis-X (SLeX) glycans, and showed the rich expression of SLeX on chicken tracheal epithelial cells. The expression and distribution of SLeX varies between species and tissue, and its affinity with the H9N2 avian influenza virus can significantly affect the viral titers on the tissue, suggesting that the fucosylation of sialic acid receptors plays an important role in the tissue tropism of the virus. Here, this project intends to investigate the role and mechanism of SLeX in the tissue tropism of H9N2 avian influenza virus. Technologies such as glycan array, mass spectrometry, CRISPR/Cas9, and molecular dynamics simulation will be applied to analyze the expression and distribution of SLeX in chicken/duck respiratory and Intestinal tissues. Key FUT genes that involved in the expression of SLeX in tissues will be identified. Finally, Then the molecular mechanism of fucosylation affecting the tissue tropism of H9N2 avian influenza virus will be revealed. Our finding will provide further knowledge for the understanding of the interaction between fucosylated receptors and influenza viruses, as well as provide experimental evidence for the construction of FUT gene engineered high-yield cell lines for avian influenza virus, and also provide references for similar studies of other virus which use glycans as receptors.