eLife assessment
This study provides valuable insight into the role of FBXO24, a member of the less characterized F-Box protein subfamily (F-box only protein) in controlling mRNA expression during spermiogenesis using loss-of-function and HA-tagged knock-in mouse models. The major strengths of the study are the rigorous phenotypic and molecular analysis by using two complementary animal models (knock-out mouse model but also HA-tagged transgenic mouse model) to determine protein levels and localization in time and space during normal spermatogenesis and in the absence of the protein. Overall, this solid study highlights the relevance and importance of FBXO24 in male fertility and provides a better understanding of the MIWI/piRNA pathway, mitochondrial organization, and chromatin condensation in mouse spermatozoa during spermiogenesis.