Univ. Grenoble Alpes, INSERM U1209, CNRS UMR 5309, Institute for Advanced Biosciences, Team Genetics Epigenetics and Therapies of Infertility, Grenoble, France.
CHU Grenoble Alpes, UM de Génétique Chromosomique, Grenoble, France.
J Med Genet. 2020 Oct;57(10):708-716. doi: 10.1136/jmedgenet-2019-106775. Epub 2020 Mar 11.
Multiple morphological abnormalities of the flagella (MMAF) consistently lead to male infertility due to a reduced or absent sperm motility defined as asthenozoospermia. Despite numerous genes recently described to be recurrently associated with MMAF, more than half of the cases analysed remain unresolved, suggesting that many yet uncharacterised gene defects account for this phenotype METHODS: Exome sequencing was performed on 167 infertile men with an MMAF phenotype. Immunostaining and transmission electron microscopy (TEM) in sperm cells from affected individuals were performed to characterise the ultrastructural sperm defects. Gene inactivation using RNA interference (RNAi) was subsequently performed in .
We identified six unrelated affected patients carrying a homozygous deleterious variants in MAATS1, a gene encoding CFAP91, a calmodulin-associated and spoke-associated complex (CSC) protein. TEM and immunostaining experiments in sperm cells showed severe central pair complex (CPC) and radial spokes defects. Moreover, we confirmed that the WDR66 protein is a physical and functional partner of CFAP91 into the CSC. Study of MAATS1's orthologue (TbCFAP91) highlighted high sequence and structural analogies with the human protein and confirmed the axonemal localisation of the protein. Knockdown of TbCFAP91 using RNAi impaired flagellar movement led to CPC defects in as observed in humans.
We showed that CFAP91 is essential for normal sperm flagellum structure and function in human and and that biallelic variants in this gene lead to severe flagellum malformations resulting in astheno-teratozoospermia and primary male infertility.
由于精子运动能力降低或缺失（定义为弱精症），导致鞭毛的多种形态异常（MMAF）一致导致男性不育。尽管最近有许多基因被描述为与 MMAF 反复相关，但分析的超过一半病例仍未解决，这表明许多尚未确定的基因缺陷导致了这种表型。方法：对 167 名具有 MMAF 表型的不育男性进行外显子组测序。对受影响个体的精子细胞进行免疫染色和透射电子显微镜（TEM）检查，以表征超微结构精子缺陷。随后使用 RNA 干扰（RNAi）对基因进行失活。结果：我们鉴定了六个不相关的受影响患者，他们携带 MAATS1 基因的纯合有害变异，该基因编码 CFAP91，一种钙调蛋白相关和辐条相关复合物（CSC）蛋白。TEM 和免疫染色实验在精子细胞中显示出严重的中央对复合物（CPC）和放射辐条缺陷。此外，我们证实 WDR66 蛋白是 CFAP91 进入 CSC 的物理和功能伴侣。对 MAATS1 的同源物（TbCFAP91）的研究强调了与人类蛋白的高序列和结构相似性，并证实了蛋白在轴丝上的定位。使用 RNAi 敲低 TbCFAP91 会损害鞭毛运动，导致 CPC 缺陷，如在人类中观察到的那样。结论：我们表明 CFAP91 对于人类和的正常精子鞭毛结构和功能是必不可少的，并且该基因的双等位基因变异导致严重的鞭毛畸形，导致弱精症和原发性男性不育。
