Deletion of the Spata3 Gene Induces Sperm Alterations and In Vitro Hypofertility in Mice.

Thanks to the analysis of an Interspecific Recombinant Congenic Strain (IRCS), we previously defined the Mafq1 quantitative trait locus as an interval on mouse Chromosome 1 associated with male hypofertility and ultrastructural abnormalities. We identified the Spermatogenesis associated protein 3 gene (Spata3 or Tsarg1) as a pertinent candidate within the Mafq1 locus and performed the CRISPR-Cas9 mediated complete deletion of the gene to investigate its function. Male mice deleted for Spata3 were normally fertile in vivo but exhibited a drastic reduction of efficiency in in vitro fertilization assays. Mobility parameters were normal but ultrastructural analyses revealed acrosome defects and an overabundance of lipids droplets in cytoplasmic remnants. The deletion of the Spata3 gene reproduces therefore partially the phenotype of the hypofertile IRCS strain.