Of note, the mitochondrial localization sequence (MLS) of GASZ is essential for GASZ to regulate spermatogenesis because the MLS deletion GASZ mutants (GaszΔNLS/ΔNLS) almost display the same phenotype with Gasz-/- mice, including male infertility but not female, diffused localization of IMC component, absent IMC, and activated transposons [32]. This evidence concerns the gene ASZ1 and male infertility.