Team Genetics Epigenetics and Therapies of Infertility, Institute for Advanced Biosciences, Université Grenoble Alpes, Inserm U1209, Centre National de la Recherche Scientifique UMR 5309, Grenoble 38000, France; Unité Médicale (UM) de Génétique Chromosomique, Centre Hospitalier Universitaire Grenoble Alpes, Grenoble 38000, France.
Team Genetics Epigenetics and Therapies of Infertility, Institute for Advanced Biosciences, Université Grenoble Alpes, Inserm U1209, Centre National de la Recherche Scientifique UMR 5309, Grenoble 38000, France; Unité Médicale (UM) de Génétique Chromosomique, Centre Hospitalier Universitaire Grenoble Alpes, Grenoble 38000, France.
Am J Hum Genet. 2019 Feb 7;104(2):331-340. doi: 10.1016/j.ajhg.2018.12.013. Epub 2019 Jan 24.
Male infertility is a major health concern. Among its different causes, multiple morphological abnormalities of the flagella (MMAF) induces asthenozoospermia and is one of the most severe forms of qualitative sperm defects. Sperm of affected men display short, coiled, absent, and/or irregular flagella. To date, six genes (DNAH1, CFAP43, CFAP44, CFAP69, FSIP2, and WDR66) have been found to be recurrently associated with MMAF, but more than half of the cases analyzed remain unresolved, suggesting that many yet-uncharacterized gene defects account for this phenotype. Here, whole-exome sequencing (WES) was performed on 168 infertile men who had a typical MMAF phenotype. Five unrelated affected individuals carried a homozygous deleterious mutation in ARMC2, a gene not previously linked to the MMAF phenotype. Using the CRISPR-Cas9 technique, we generated homozygous Armc2 mutant mice, which also presented an MMAF phenotype, thus confirming the involvement of ARMC2 in human MMAF. Immunostaining experiments in AMRC2-mutated individuals and mutant mice evidenced the absence of the axonemal central pair complex (CPC) proteins SPAG6 and SPEF2, whereas the other tested axonemal and peri-axonemal components were present, suggesting that ARMC2 is involved in CPC assembly and/or stability. Overall, we showed that bi-allelic mutations in ARMC2 cause male infertility in humans and mice by inducing a typical MMAF phenotype, indicating that this gene is necessary for sperm flagellum structure and assembly.
男性不育是一个主要的健康问题。在其不同的原因中，鞭毛的多种形态异常（MMAF）导致弱精症，是最严重的精子质量缺陷形式之一。受影响男性的精子显示短、卷曲、缺失和/或不规则的鞭毛。迄今为止，已经发现六个基因（DNAH1、CFAP43、CFAP44、CFAP69、FSIP2 和 WDR66）与 MMAF 反复相关，但分析的一半以上病例仍未解决，这表明许多尚未确定的基因缺陷导致了这种表型。在这里，对 168 名具有典型 MMAF 表型的不育男性进行了全外显子组测序（WES）。五个无亲缘关系的受影响个体携带 ARMC2 的纯合有害突变，该基因以前与 MMAF 表型无关。使用 CRISPR-Cas9 技术，我们产生了 ARMC2 纯合突变的小鼠，它们也表现出 MMAF 表型，从而证实了 ARMC2 参与了人类 MMAF。在 ARMC2 突变个体和突变小鼠的免疫染色实验中，证据表明轴丝中心对复合物（CPC）蛋白 SPAG6 和 SPEF2 的缺失，而其他测试的轴丝和轴周成分存在，表明 ARMC2 参与 CPC 的组装和/或稳定性。总的来说，我们表明 ARMC2 的双等位基因突变通过诱导典型的 MMAF 表型导致人类和小鼠的男性不育，表明该基因对于精子鞭毛结构和组装是必要的。
