Lrriq1 is an essential factor for fertility by suppressing apoptosis

Leucine-rich repeats and IQ motif containing 1 (LRRIQ1) gene is reportedly associated with plasma inhibin B levels. However, the function of LRRIQ1 remains unknown. In this study, we generated Lrriq1 knockout mice (Lrriq1^-/- mice) and examined the effects of LRRIQ1 on inhibin B and fertility.

Lrriq1^-/- mice were generated using CRISPR/Cas9 genome editing technology. The expression of Inhibin B was examined by Western blotting using a protein extracted from the testis of a 3-month-old male mouse. Mating experiments were conducted using 7-week-old Lrriq1^-/- mice and wild-type (WT) mice to examine fertility. Sperm concentration and sperm motility were measured using 3-month-old male mice.

Expression analysis of inhibin B revealed that Lrriq1^-/- mice exhibited reduced mRNA and protein levels of inhibin alpha (Inha), which constitutes the α subunit. In the mating experiment, the litter size of Lrriq1^-/- male mice was 4.3 ± 2.9, which was significantly lower than that of WT male mice (8.3 ± 1.3) (p < 0.001). No difference in sperm count was observed between Lrriq1^-/- and WT male mice; however, sperm motility (%) was significantly reduced in Lrriq1^-/- mice (48.4 ± 4.9) when compared with WT mice (70.2 ± 4.7) (p < 0.001). Based on TUNEL staining, the testes and epididymal sperm of Lrriq1^-/- mice showed high numbers of apoptosis-positive cells.

Lrriq1 knockout reduced sperm motility and litter size by inducing apoptosis of testicular germ cells and epididymal sperm.