is essential for rat spermatogenesis and fertility.

Knockout rats were generated due to its potential involvement in myopia. Subsequent study suggested that the homozygous truncation variants in is associated with male fertility but not myopia. Sperm count and sperm motility were measured in male rats. HE staining, immunofluorescence staining and TUNEL staining were used to observe the gross and histopathology of testis in homozygous and wild rats. knockout rats were generated by CRISPR/Cas9 gene editing. In the process of breeding rats, homozygous male rats were noted to be infertile, with significantly decreased number of sperm suggesting cryptozoospermia that was further confirmed by histologic studies. TUNEL assay showed an increased apoptosis in homozygous testes compared with wild type (<0.001). A significant reduction of spermatocytes was observed in homozygotes compared with wild type (=0.025) by immunofluorescence. These results suggest that is critical for spermatogenesis in male rats.