Cabs1 Maintains Structural Integrity of Mouse Sperm Flagella during Epididymal Transit of Sperm

The calcium-binding protein spermatid-associated 1 (Cabs1) is a novel spermatid-specific protein. However, its function remains largely unknown. In this study, we found that long noncoding RNA (lncRNA) transcripted from the Cabs1 gene antisense, AntiCabs1, was also exclusively expressed in spermatids. and AntiCabs1 knockout mice were generated separately (using Clustered Regularly Interspaced Short Palindromic Repeat (CRISPR)-Cas9 methods) to investigate their functions spermatogenesis. genetic loss of did not affect testicular epididymal development; however, male exhibited significantly impaired sperm tail structure subfertility. Ultrastructural analysis revealed defects flagellar differentiation leading an abnormal annulus disorganization midpiece–principal piece junction, which may explain high proportion with bent tail. Interestingly, increased during transit epididymis. Furthermore, Western blot immunofluorescence analyses showed decreased Septin 4 Krt1 cyclin Y-like (Ccnyl1) levels compared wild type, suggesting deficiency disturbed expression cytoskeleton-related proteins. By contrast, AntiCabs1−/− indistinguishable type regarding development, morphology, concentration motility, fertility. This study demonstrates important component essential for proper assembly motility.