Trypanosome Cell Biology Unit, Institut Pasteur and INSERM U1201, Paris, France.
Trypanosome Transmission Group, Institut Pasteur, Paris, France.
Cell Microbiol. 2021 Sep;23(9):e13347. doi: 10.1111/cmi.13347. Epub 2021 May 14.
The single flagellum of African trypanosomes is essential in multiple aspects of the parasites' development. The FLAgellar Member 8 protein (FLAM8), localised to the tip of the flagellum in cultured insect forms of Trypanosoma brucei, was identified as a marker of the locking event that controls flagellum length. Here, we investigated whether FLAM8 could also reflect the flagellum maturation state in other parasite cycle stages. We observed that FLAM8 distribution extended along the entire flagellar cytoskeleton in mammalian-infective forms. Then, a rapid FLAM8 concentration to the distal tip occurs during differentiation into early insect forms, illustrating the remodelling of an existing flagellum. In the tsetse cardia, FLAM8 further localises to the entire length of the new flagellum during an asymmetric division. Strikingly, in parasites dividing in the tsetse midgut and in the salivary glands, the amount and distribution of FLAM8 in the new flagellum were seen to predict the daughter cell fate. We propose and discuss how FLAM8 could be considered a meta-marker of the flagellum stage and maturation state in trypanosomes.
非洲锥虫的单根鞭毛在寄生虫发育的多个方面都是必不可少的。FLAgellar Member 8 蛋白（FLAM8）在培养的布氏锥虫的昆虫形式的鞭毛顶端被定位，被鉴定为控制鞭毛长度的锁定事件的标志物。在这里，我们研究了 FLAM8 是否也可以反映其他寄生虫周期阶段的鞭毛成熟状态。我们观察到，在哺乳动物感染形式中，FLAM8 的分布沿着整个鞭毛细胞骨架延伸。然后，在早期昆虫形式分化过程中，FLAM8 迅速集中到远端尖端，说明了现有鞭毛的重塑。在采采蝇心脏中，FLAM8 在不对称分裂过程中进一步定位到新鞭毛的整个长度。引人注目的是，在采采蝇中肠和唾液腺中分裂的寄生虫中，新鞭毛中 FLAM8 的数量和分布被认为可以预测子细胞的命运。我们提出并讨论了 FLAM8 如何被视为锥虫鞭毛阶段和成熟状态的元标志物。
