PDF(Pubmed)
Abstract：
Dynein complexes are large, multi-unit assemblies involved in many biological processes via their critical roles in protein transport and axoneme motility. Using next-generation sequencing of infertile men presenting with low or no sperm in their ejaculates, we identified damaging variants in the dynein-related gene AXDND1. We thus hypothesised that AXDND1 is a critical regulator of male fertility. To test this hypothesis, we produced a knockout mouse model. Axdnd1-/- males were sterile at all ages but presented with an evolving testis phenotype wherein they could undergo one round of histologically replete spermatogenesis followed by a rapid depletion of the seminiferous epithelium. Marker experiments identified a role for AXDND1 in maintaining the balance between differentiation-committed and self-renewing spermatogonial populations, resulting in disproportionate production of differentiating cells in the absence of AXDND1 and increased sperm production during initial spermatogenic waves. Moreover, long-term spermatogonial maintenance in the Axdnd1 knockout was compromised, ultimately leading to catastrophic germ cell loss, destruction of blood-testis barrier integrity and immune cell infiltration. In addition, sperm produced during the first wave of spermatogenesis were immotile due to abnormal axoneme structure, including the presence of ectopic vesicles and abnormalities in outer dense fibres and microtubule doublet structures. Sperm output was additionally compromised by a severe spermiation defect and abnormal sperm individualisation. Collectively these data identify AXDND1 as an atypical dynein complex-related protein with a role in protein/vesicle transport of relevance to spermatogonial function and sperm tail formation in mice and humans. This study underscores the importance of studying the consequences of gene loss-of-function on both the establishment and maintenance of male fertility.
摘要：
Dynein复合物很大，多单元组件通过其在蛋白质运输和轴突运动中的关键作用参与许多生物过程。使用下一代测序的不育男性，他们的射精中精子含量低或没有精子，我们在动力蛋白相关基因AXDND1中发现了破坏性变异.因此，我们假设AXDND1是男性生育力的关键调节因子。为了检验这个假设，我们制作了一个敲除小鼠模型。Axdnd1-/-雄性在所有年龄段都是不育的，但具有不断发展的睾丸表型，其中它们可以经历一轮组织学上充分的精子发生，然后快速消耗生精上皮。标记实验确定了AXDND1在维持分化定向精原种群和自我更新精原种群之间的平衡中的作用，在没有AXDND1的情况下，导致分化细胞的不成比例的产生，并在最初的生精波中增加了精子的产生。此外，Axdnd1敲除的长期精原维持受损，最终导致灾难性的生殖细胞损失，破坏血-睾丸屏障的完整性和免疫细胞浸润。此外,由于轴突结构异常，在第一波精子发生过程中产生的精子不运动，包括异位囊泡的存在以及外部致密纤维和微管双态结构的异常。严重的精子缺陷和异常的精子个体化还损害了精子输出。总的来说，这些数据将AXDND1鉴定为非典型动力蛋白复合物相关蛋白，在与小鼠和人类精原功能和精子尾巴形成相关的蛋白/囊泡转运中起作用。这项研究强调了研究基因功能丧失对男性生育力的建立和维持的影响的重要性。
