Investigating the role of a testis-expressed gene Tex2 in spermatogenesis in mice.

The testis-expressed (TEX/Tex) genes are highly expressed in the testes of various species. Several members of the TEX catalog have been suggested to play a role in spermatogenesis, but the functions of most members remain unknown. Here, we initially confirmed that TEX2 is significantly upregulated in spermatids and further successfully generated a Tex2 knockout (KO) mouse model using CRISPR/Cas9 technology. However, we found that the Tex2 KO male mice were fertile. Interestingly, Papanicolaou staining and scanning electron microscopy showed slight abnormalities in sperm morphology and reduced sperm motility as assessed by computer-assisted sperm analysis in Tex2 KO mice. Collectively, despite Tex2 having enriched expression in mouse testis, our genetic KO studies revealed that Tex2 is not essential for spermatogenesis or fertility in male mice, although its absence in sperm causes subtle abnormalities in morphology and motility.