Analysis of host invasion mechanisms of Plasmodium sporozoites focusing on rhoptry proteins.

为了阐明疟原虫子孢子侵入靶细胞的分子机制，我们试图鉴定子孢子中的棒状体蛋白。通过基因表达、蛋白表达和定位分析，鉴定了8个新的子孢子棒状体分子。由于这些蛋白质也在裂殖子中表达，因此需要开发子孢子阶段特异性基因沉默系统用于功能分析。为了实现该目的，进行了合适的候选启动子的筛选以进行交换。利用同源重组系统将原始启动子与候选启动子进行交换，成功地获得了子孢子阶段特异性基因沉默转基因寄生虫。利用该系统，表明其中一个棒状体蛋白参与子孢子唾液腺侵袭。

To elucidate the molecular mechanisms of Plasmodium sporozoite invasion of the target cells, we attempted to identify rhoptry proteins in sporozoites. Gene expression, protein expression and localization analyses in sporozoites were performed, then 8 novel sporozoite rhoptry molecules were identified. Since these proteins are also expressed in merozoites, development of sporozoite stage-specific gene silencing system is required for functional analysis. To achieve this purpose, screening for suitable candidate promoters to swap was performed. By swapping the original promoter with the candidate promoter using homologous recombination system, we succeeded to generate sporozoite stage-specific gene silencing transgenic parasites. Using this system, it was indicated that one of the rhoptry proteins is involved in sporozoite salivary gland invasion.