Ccer1 is a spermatid-specific gene required for spermatogenesis and male fertility.

Male infertility is a multifactorial condition for which the underlying causes frequently remain undefined. Genetic factors have long been associated with male fertility. However, many of them are poorly or not at all characterized and their biological functions are unknown. Identifying the key genes behind male infertility is crucial for improving prognosis and treatment options, as well as for evaluating the risk of passing on genetic defects through natural or assisted reproductive methods to the next generation. Here, we have studied the Coiled-coil domain-containing glutamate-rich protein 1 (Ccer1), a poorly characterized gene specific to vertebrates. We demonstrate that it is enriched during spermiogenesis in spermatids in both mice and humans. The studied Ccer1 knockout mice exhibit significant subfertility due to the absence of Ccer1 function, which leads to altered sperm head and tail ultrastructure. This study defines Ccer1 as a spermatid-specific gene critical for spermiogenesis, suggesting it would be worthwhile inspecting when there is a suspicion of male infertility associated with genetic causes.