G3BP2, a stress granule assembly factor, is dispensable for spermatogenesis in mice

BACKGROUND: Spermatogenesis is a complex process that includes mitosis, meiosis, and spermiogenesis. During spermatogenesis, genetic factors play a vital role inthe formation of properly functioning sperm. GTPase-activating protein (SH3 domain)-binding protein 2 (G3BP2) is known to take part in immune responses, mRNA transport, and stress-granule assembly. However, its role in male fertility is unclear. Here, we generated a G3bp2 conditional knockout (cKO) mouse model to explore the function of G3BP2 in male fertility. METHODS: Polymerase chain reaction (PCR) and western blotting (WB) were used to confirm testis-specific G3bp2 knockout. Hematoxylin-eosin (HE) staining to observe testicular morphology and epididymal structure. Computer-aided sperm analysis (CASA) to detect sperm concentration and motility. Terminal deoxynucleotidyl transferase-dUTP nick-end labeling (TUNEL) assay was used to detect apoptotic cells. RESULTS: We found that cKO male mice are fertile with the normal morphology of the testis and sperm. Additionally, CASA of the semen from cKO mice showed that they all had a similar sperm concentration and motility. In addition, sperm from these mice exhibited a similar morphology. But the tunnel assay revealed increased apoptosis in their testes relative to the level in the wild type (WT). CONCLUSION: Together, our data demonstrate that G3BP2 is dispensable for spermatogenesis and male fertility in mice albeit with the increased germ-cell apoptosis.