School of Life Sciences, Queens Medical Centre, University of Nottingham, Nottingham, UK.
Department of Biological and Medical Sciences, Faculty of Health and Life Science, Oxford Brookes University, Oxford, UK.
Life Sci Alliance. 2019 Aug 13;2(4). doi: 10.26508/lsa.201900488. Print 2019 Aug.
Eukaryotic flagella are conserved microtubule-based organelles that drive cell motility. , the causative agent of malaria, has a single flagellate stage: the male gamete in the mosquito. Three rounds of endomitotic division in male gametocyte together with an unusual mode of flagellum assembly rapidly produce eight motile gametes. These processes are tightly coordinated, but their regulation is poorly understood. To understand this important developmental stage, we studied the function and location of the microtubule-based motor kinesin-8B, using gene-targeting, electron microscopy, and live cell imaging. Deletion of the gene showed no effect on mitosis but disrupted 9+2 axoneme assembly and flagellum formation during male gamete development and also completely ablated parasite transmission. Live cell imaging showed that kinesin-8B-GFP did not co-localise with kinetochores in the nucleus but instead revealed a dynamic, cytoplasmic localisation with the basal bodies and the assembling axoneme during flagellum formation. We, thus, uncovered an unexpected role for kinesin-8B in parasite flagellum formation that is vital for the parasite life cycle.
真核生物鞭毛是保守的微管细胞器，能驱动细胞运动。疟原虫是疟疾的病原体，它只有一个鞭毛阶段：蚊子中的雄性配子。雄性配子体中的三轮有丝分裂，加上一种不寻常的鞭毛组装方式，迅速产生了 8 个游动的配子。这些过程是紧密协调的，但它们的调节机制还不清楚。为了了解这个重要的发育阶段，我们使用基因靶向、电子显微镜和活细胞成像技术，研究了基于微管的马达蛋白 kinesin-8B 的功能和定位。敲除 基因对有丝分裂没有影响，但破坏了 9+2 轴丝的组装和雄性配子发育过程中的鞭毛形成，也完全消除了寄生虫的传播。活细胞成像显示，kinesin-8B-GFP 没有与核内的动粒共定位，而是在鞭毛形成过程中与基体和组装的轴丝一起呈现出动态的细胞质定位。因此，我们揭示了 kinesin-8B 在寄生虫鞭毛形成中的一个意想不到的作用，这对寄生虫的生命周期至关重要。
