Effects of Fscb/Cabyr double gene knockout on reproductive capacity in male mice

Abstract

Objective To evaluate the value of CABYR protein and its complex with FSCB in maintaining sperm fertilization ability and investigate the possible mechanism of physiological function of the coruplex by observing the natural fertility of Fscb/Cabyr double gene knockout and Cabyr single gene knockout male mice. Methods Fscb/Cabyr (--/--) double gene knockout male mice, Fscb/Cabyr (++/--) single gene knockout male mice and wild background male mice were mated with wild-type female mice respectively, and the pregnancy and litter production of female mice in each group were observed. The sperm of male mice with different genotypes were labeled with Fluo-4 AM calcium fluorescent probe in vitro and observed under fluorescence microscope, and the level of calcium ion in the sperm were detected by ELISA; The expression of CATSPER channel proteins in sperm of mice with different genotypes was measured by Western blotting. Results All the male mice with Fscb/Cabyr (--/--) double gene knockout and Fscb/Cabyr (++/--) single gene knockout lost their reproductive capacity completely, and failed to make any female mice pregnant and give birth. Compared with the wild-type male mice, the sperm calcium ion concentration of Fscb/Cabyr (--/--) and Fscb/Cabyr (++/--) male mice was decreased significantly (P < 0.000 1); The expression of CATSPER-1 protein in the sperm of Fscb/Cabyr(--/--) mice was decreased obviously. The expression of CATSPER-4 in the sperm of Fscb/Cabyr(--/--) and Fscb/Cabyr(++/--) mice were notably decreased. Conclusion The deletion of either CABYR or FSCB/CABYR protein complex in male sperm leads to the loss of reproductive function in the male mice, which may be realized by affecting the expression of calcium channel proteins CATSPER-1 and CATSPER-4, concentration of calcium ions in sperm, and then motility function of sperm.

Keywords

• gene knockout
• sperm
• fibrous sheath
• insemination
• calcium channel