巴贝斯虫病是由巴贝虫属的血液原虫引起的一种重要的动物和人的寄生虫病。上个世纪研制的疫苗和药物已不能满足对该病有效防治的需求，原因之一是目前巴贝斯虫感染、致病和传播等方面的分子机制不清，导致新型疫苗和药物的研发缺乏基础理论支撑。血小板反应蛋白相关匿名蛋白（TRAPs）是顶复门寄生虫微线体分泌的一类Ⅰ型跨膜蛋白，其成员在寄生虫运动、入侵和出胞等生命活动中行使多种功能。为弄清巴贝斯虫裂殖子TRAPs的特征和在虫体运动和进出宿主细胞过程中的作用机制，本项目以羊巴贝斯虫新疆株为研究对象，首先应用BLAST、HMMER等生物信息学分析技术鉴定TRAP蛋白家族成员，分析其结构特征、表达丰度和天然TRAPs的大小；然后构建稳定表达TRAPs的虫株，分析其在虫体内的亚细胞定位，鉴定与其互作的蛋白分子，初步确定TRAPs可能参与的生物学过程；最后应用CRISPR/Cas9及同源重组技术，构建traps基因缺失/突变/补全虫株，比较野生株和突变/缺失/补全株裂殖子的运动能力、入侵红细胞的效率和传代培养生长特征，验证其对巴贝斯虫运动和进出红细胞的影响和关键功能位点。本研究将为阐明巴贝斯虫运动和入侵宿主细胞机制，寻找新的药物和疫苗靶点提供理论依据。

Babesiosis is an important tick-borne, parasitic disease of animals and humans, caused by haemoprotozoans of the genus Babesia. The vaccines and medicines developed in last century can not meet the demand of efficient control this disease at present. One of reason is that molecular mechanisms of infection, pathogenesis and transmission of Babesia are not clear, which causes there are the knowledge gaps for developing new vaccines and medicines. The thrombospondin -related anonymous proteins (TRAPs), a kind of type-I transmembrane protein secreted by apicomplexan micronemes, play various functions during the parasite performing the biological process, such as locomotion, invasion and egression. For clarifying the features and molecular mechanisms of Babesia TRAPs in merozoites motility and invading and egressing host cells, we focus on the Babesia sp. Xinjiang infective to sheep. Firstly we purpose to identify members of TRAP family and analyze their gene structural characteristics, expression levels and sizes of natural TRAPs. And then, the transgenic Babesia sp Xinjiang strains that can stably overexpress TRAPs will be constructed. Subcellular location and interacting proteins of TRAPs in merozoites will be illuminated using the transgenic strains so as to preliminarily define the roles of Babesia TRAPs during merozoite carrying out the biological processes, such as locomotion, invasion or egression. Finally, the transgenic Babesia sp Xinjiang strains that are trap gene deleted (BXJTRAP cKO), mutant (BXJFFTRAP/BXJTRAP mu) or complemented (BXJTRAP cKO/TRAP) will be constructed using CRISPR/Cas9 genome editing system and homologous recombination technique. The effects and key functional sites of Babesia TRAPs during merozoite locomotion and ingress or egress erythrocytes will be identified by the comparisons features of wild type, BXJTRAP cKO, BXJFFTRAP/ BXJTRAP mu and BXJTRAP cKO/TRAP Babesia strains in the aspect of motility, efficiency of invading erythrocytes and growth characteristics of subculture. This project will provide foundation of academic data for uncovering the mechanism of Babesia locomotion and invading host cells, and for seeking new targets for chemotherapeutics and immunoprophylaxis of babesiosis.