CARF regulates the alternative splicing and piwi/piRNA complexes during mouse spermatogenesis through PABPC1

• CARF deficiency in male mice leads to impaired spermatogenesis and reduced fertility, highlighting its essential role in male reproduction. • CARF interacts with key splicing factors including PABPC1 and directly targets 356 mRNAs in spermatocytes, indicating its broad regulatory impact on alternative splicing. • Loss of CARF causes aberrant splicing patterns in its target mRNAs, which may underlie the observed spermatogenic defects. • CARF modulates PIWIL1 expression and localization via PABPC1 downregulation, affecting pachytene-piRNA ratios and potentially impacting piRNA-mediated gene silencing.