1Shimoda Marine Research Center, University of Tsukuba, Shimoda, 415-0025 Japan.
2Department of Reproductive Biology, National Center for Child Health and Development, Tokyo, 157-8535 Japan.
Commun Biol. 2019 Jun 20;2:226. doi: 10.1038/s42003-019-0462-y. eCollection 2019.
Calaxin is a Ca-binding dynein-associated protein that regulates flagellar and ciliary movement. In ascidians, calaxin plays essential roles in chemotaxis of sperm. However, nothing has been known for the function of calaxin in vertebrates. Here we show that the mice with a null mutation in , which encodes calaxin, display typical phenotypes of primary ciliary dyskinesia, including hydrocephalus, , and abnormal motility of trachea cilia and sperm flagella. Strikingly, both males and females are viable and fertile, indicating that calaxin is not essential for fertilization in mice. The 9 + 2 axonemal structures of epithelial multicilia and sperm flagella are normal, but the formation of 9 + 0 nodal cilia is significantly disrupted. Knockout of calaxin in zebrafish also causes due to the irregular ciliary beating of Kupffer's vesicle cilia, although the 9 + 2 axonemal structure appears to remain normal.
Calaxin 是一种与肌球蛋白相关的钙结合蛋白，可调节鞭毛和纤毛的运动。在海鞘中，calaxin 在精子的趋化性中发挥重要作用。然而，在脊椎动物中，calaxin 的功能尚不清楚。在这里，我们发现编码 calaxin 的 基因缺失的小鼠表现出典型的原发性纤毛运动障碍表型，包括脑积水、多尿和气管纤毛及精子鞭毛运动异常。值得注意的是，雌雄小鼠均可存活并具有生育能力，表明 calaxin 并非小鼠受精所必需。上皮性多纤毛和精子鞭毛的 9+2 轴丝结构正常，但 9+0 位纤毛的形成明显受到破坏。斑马鱼中 calaxin 的敲除也会导致 ，这是由于滤胞纤毛的不规则摆动。尽管 9+2 轴丝结构似乎保持正常。
