Epididymal maturation is critical for acquisition of motility and fertilizing capacity by sperm. During epididymal transit, the surface of sperm undergoes prominent sequential changes through interactions with secreted proteins, including protease inhibitors. In the present study, we characterized three epididymis-specific SPINKs (serine protease inhibitors, Kazal-type): SPINK8, SPINK11, and SPINK12. We found that these epididymal SPINKs are expressed in an epididymal region-specific manner and their expression is developmentally regulated. Remarkably, cellular analyses revealed that SPINK8 and SPINK12 are transferred to the sperm. To investigate the in vivo properties of SPINK12, we analyzed knockout mice generated by CRISPR/Cas9-mediated genome editing. Loss of SPINK12 did not alter epididymal tubule structure or sperm phenotypes. Spink12 mutant mice exhibited normal fertility, suggesting that SPINK12 is functionally redundant in the epididymis.

附睾成熟对于精子获得活力和受精能力至关重要。在附睾转运过程中，精子表面通过与分泌的蛋白质（包括蛋白酶抑制剂）相互作用而经历显着的顺序变化。在本研究中，我们表征了三种附睾特异性SPINK（丝氨酸蛋白酶抑制剂，Kazal型）：SPINK8，SPINK11和SPINK12。我们发现这些附睾SPINKs以附睾区域特异的方式表达，其表达受到发育调控。值得注意的是，细胞分析显示SPINK8和SPINK12已转移至精子。调查体内SPINK12的特性，我们分析了由CRISPR / Cas9介导的基因组编辑产生的敲除小鼠。丢失SPINK12不会改变附睾小管结构或精子表型。Spink12突变小鼠表现出正常的生育能力，这表明SPINK12在附睾中功能上是多余的。