腭裂是颅颌面常见的出生缺陷，影响患者口颌系统功能、颅颌面发育及心理健康等。腭裂致病基因的鉴定及功能解析是腭裂早期分子诊断的关键。申请者前期在一个非综合征型腭裂家系中发现了位于HER2基因上的一个错义突变（A87T），并针对该突变进行了体外细胞分子实验及体内非洲爪蟾胚胎实验，初步推测HER2是一个非综合征型腭裂新致病基因。本申请中，为了回答“HER2是否为非综合征型腭裂新致病基因？A87T突变影响HER2蛋白功能的分子机制是什么？”这两个科学问题，本研究拟：（1）绘制Her2在小鼠腭部发育阶段单细胞分辨率表达谱；（2）在细胞和分子水平确认A87T突变对HER2自身活性和下游信号的影响；（3）在非洲爪蟾胚胎中评估HER2及A87T突变对口腭部发育的影响。本项目将拓展我们对于HER2信号在颅颌面发育中作用的理解，为腭裂的早期预防提供更多的理论基础。

Cleft palate is a common craniofacial birth defect, affecting the function of the oral and maxillofacial system, craniofacial development, and mental health in patients. The key to early molecular diagnosis of cleft palate is to identify novel cleft palate genes and further elucidate their functional roles. In our preliminary study, we have found a missense mutation (A87T) in HER2 gene in a non-syndromic cleft palate pedigree. Our in vitro cellular and molecular experiments and in vivo Xenopus embryos experiments have indicated HER2 might be a novel non-syndromic cleft palate pathogenic gene. In this project, we aim to address these two questions: “Is HER2 a novel non-syndromic cleft palate pathogenic gene? And, how does the A87T mutation affect the molecular function of HER2?”. We are planning to conduct research: (1) mapping the single-cell resolution expression pattern of Her2 gene in the developing palate of mice; (2) confirming the effects of A87T mutation on the activities of HER2 itself and downstream signaling effectors at the cellular and molecular levels; (3) assessing the effects of HER2 and A87T mutation on the development of mouth and palate in Xenopus embryos. This project will improve our knowledge of the role of HER2 signaling in craniofacial development and provide more theoretical basis for early prevention of cleft palate.