Department of Andrology, Women and Children's Hospital, School of Medicine, Xiamen University, Xiamen, Fujian, China.
Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, China.
Front Endocrinol (Lausanne). 2024 Oct 28;15:1462509. doi: 10.3389/fendo.2024.1462509. eCollection 2024.
Oligoasthenoteratozoospermia (OAT) is a widespread cause of male infertility. One of the usual clinical manifestations of OAT is multiple morphological abnormalities of the sperm flagella (MMAF), which are frequently associated with mutations and defects in the dynein family. However, the relationship between the newly identified Dynein Axonemal Heavy Chain 3 (DNAH3) mutation and oligonasthenospermia in humans has not yet been established.
Whole exome sequencing, pathogenicity analysis, and species conservation analysis of mutation sites were conducted on two patients from different unrelated families with DNAH3 mutations. We identified representative mutation sites and predicted the protein structure following these mutations. The sperm characteristics of the two patients with DNAH3 mutations were verified using Papanicolaou staining, scanning electron microscopy, and transmission electron microscopy. Additionally, mRNA and protein levels were assessed through RT-qPCR and Western blotting.
The biallelic mutations in the first progenitor included a heterozygous deletion and insertion, c.6535_6536 delinsAC (to infect mutation (p.Asp2179Thr), and stop codon premutation, c.3249G > A (p.Trp1083Ter). In Family II, the patient (P2) harbored a DNAH3 heterozygous missense mutation, c. 10439G> A(p.Arg3480Gln), along with a stop codon premutation, (c.10260G > A; p.Trp3420Ter). Patients with premature termination of transcription or translation due to DNAH3 mutations exhibit OAT phenotypes, including fibrous sheath dysplasia and multiple tail malformations. We identified the representative sites after mutation, predicted the protein structure, and assessed changes in the protein levels of DNAH3 and related genes following mutations. Notably,a significant reduction in DNAH3 protein expression was validated in these patients. We may explore in the future how DNAH3 affects sperm motility and quality through regulatory mechanisms involving protein structural changes.
Novel biallelic mutations in DNAH3, especially those resulting in a premature stop codon, may alter protein expression, structure, and active site, leading to spermatogenic failure and potentially inducing OAT. The discovery of new mutations in DNAH3 may be the key to the diagnosis and treatment of OAT.
少弱畸形精子症（OAT）是男性不育的常见原因。OAT 的一种常见临床表现是精子鞭毛的多种形态异常（MMAF），其通常与轴丝动力蛋白家族的突变和缺陷有关。然而，新发现的轴丝动力蛋白重链 3（DNAH3）突变与人类少弱精子症之间的关系尚未建立。
对来自两个不同无亲缘关系的具有 DNAH3 突变的家庭的两名患者进行全外显子组测序、致病性分析和突变位点的种系保守性分析。我们鉴定了代表性突变位点，并对这些突变后的蛋白质结构进行了预测。使用巴氏染色、扫描电子显微镜和透射电子显微镜验证了这两名具有 DNAH3 突变的患者的精子特征。此外，通过 RT-qPCR 和 Western blot 评估了 mRNA 和蛋白质水平。
第一个前体的双等位基因突变包括杂合缺失和插入，c.6535_6536 delinsAC（致突变（p.Asp2179Thr）和终止密码子前突变，c.3249G > A（p.Trp1083Ter）。在家族 II 中，患者（P2）携带 DNAH3 杂合错义突变，c.10439G > A（p.Arg3480Gln），同时存在终止密码子前突变（c.10260G > A；p.Trp3420Ter）。由于 DNAH3 突变导致转录或翻译提前终止的患者表现出 OAT 表型，包括纤维鞘发育不良和多个尾部畸形。我们鉴定了突变后的代表性位点，预测了蛋白质结构，并评估了突变后 DNAH3 和相关基因的蛋白质水平变化。值得注意的是，在这些患者中验证了 DNAH3 蛋白表达的显著减少。我们未来可能会探讨 DNAH3 通过涉及蛋白质结构变化的调节机制如何影响精子运动和质量。
DNAH3 的新的双等位基因突变，特别是导致提前终止密码子的突变，可能改变蛋白质的表达、结构和活性部位，导致生精失败，并可能导致 OAT。在 DNAH3 中发现新的突变可能是 OAT 诊断和治疗的关键。
