DNAH2, also known as Dynein Axonemal Heavy Chain 2, is crucial for sperm flagella formation and may be involved in DNA repair pathways. In the context of sperm development, it is essential for multiple steps in the formation of sperm flagella, and its function is related to the normal motility of sperm. Additionally, it may play a role in the homologous recombination repair pathway of Fanconi anemia (FA) [1,2,3,4,5].

In human and mouse studies, genetic defects in DNAH2 underlie male infertility with multiple morphological abnormalities of the sperm flagella (MMAF). Dnah2 -null male mice are infertile, and their sperm cells display absent, short, bent, coiled, and/or irregular flagella, consistent with the MMAF phenotype. The absence of DNAH2 compromises the expression of other axonemal components such as DNAH1 and RSPH3, suggesting its importance in flagella development [3]. In U2OS cells, downregulation of DNAH2 increases cell sensitivity to DNA inter-strand crosslinks, reduces the enrichment of FANCD2 protein to DNA damage sites, and influences the ubiquitination modification level of FANCD2, indicating its potential role in the FA homologous recombination repair pathway [1].

In conclusion, DNAH2 is essential for sperm flagella formation, playing a significant role in male fertility. Its role in the homologous recombination repair pathway of FA also indicates its importance in DNA repair-related disease mechanisms. Studies using gene-knockout mouse models have been crucial in revealing these functions, providing insights into the molecular and cellular mechanisms of MMAF pathogenesis and FA-related DNA repair processes.