Persico Veronica, Callaini Giuliano, Riparbelli Maria Giovanna
Department of Life Sciences, University of Siena, Siena, Italy.
Department of Medical Biotechnologies, University of Siena, Siena, Italy.
Front Cell Dev Biol. 2019 Aug 21;7:173. doi: 10.3389/fcell.2019.00173. eCollection 2019.
The precursor of the flagellar axoneme is already present in the primary spermatocytes of . During spermatogenesis each primary spermatocyte shows a centriole pair that moves to the cell membrane and organizes an axoneme-based structure, the cilium-like region (CLR). The CLRs persist through the meiotic divisions and are inherited by young spermatids. During spermatid differentiation the ciliary caps elongate giving rise to the sperm axoneme. Mutations in Klp10A, a kinesin-13 of , results in defects of centriole/CLR organization in spermatocytes and of ciliary cap assembly in elongating spermatids. Reduced Klp10A expression also results in strong structural defects of sensory type I neurons. We show, here, that this protein displays a peculiar localization during male gametogenesis. The Klp10A signal is first detected at the distal ends of the centrioles when they dock to the plasma membrane of young primary spermatocytes. At the onset of the first meiotic prometaphase, when the CLRs reach their full size, Klp10A is enriched in a distinct narrow area at the distal end of the centrioles and persists in elongating spermatids at the base of the ciliary cap. We conclude that Klp10A could be a core component of the ciliary transition zone in
鞭毛轴丝的前体已存在于……的初级精母细胞中。在精子发生过程中，每个初级精母细胞都有一对中心粒，它们移向细胞膜并形成一个基于轴丝的结构，即类纤毛区（CLR）。CLR在减数分裂过程中持续存在，并由年轻的精子细胞继承。在精子细胞分化过程中，纤毛帽伸长，形成精子轴丝。Klp10A（一种……的驱动蛋白-13）的突变导致精母细胞中中心粒/CLR组织缺陷以及伸长精子细胞中纤毛帽组装缺陷。Klp10A表达降低还会导致感觉I型神经元出现严重的结构缺陷。我们在此表明，该蛋白在雄性配子发生过程中表现出特殊的定位。当中心粒对接至年轻初级精母细胞的质膜时，首先在中心粒的远端检测到Klp10A信号。在第一次减数分裂前期开始时，当CLR达到其全长时，Klp10A在中心粒远端的一个明显狭窄区域富集，并在伸长精子细胞的纤毛帽基部持续存在。我们得出结论，Klp10A可能是……中纤毛过渡区的核心成分。
