Pachytene PIWI-interacting RNAs (piRNAs), which comprise >80% of small RNAs in the adult mouse testis, have been proposed to bind and regulate target RNAs like microRNAs, cleave targets like short interfering RNAs or lack biological function altogether. Although piRNA pathway protein mutants are male sterile, no biological function has been identified for any mammalian piRNA-producing locus. Here, we report that males lacking piRNAs from a conserved mouse pachytene piRNA locus on chromosome 6 (pi6) produce sperm with defects in capacitation and egg fertilization. Moreover, heterozygous embryos sired by pi6^−/− fathers show reduced viability in utero. Molecular analyses suggest that pi6 piRNAs repress gene expression by cleaving messenger RNAs encoding proteins required for sperm function. pi6 also participates in a network of piRNA–piRNA precursor interactions that initiate piRNA production from a second piRNA locus on chromosome 10, as well as pi6 itself. Our data establish a direct role for pachytene piRNAs in spermiogenesis and embryo viability.

粗线期 PIWI 相互作用 RNA (piRNA) 在成年小鼠睾丸中占超过 80% 的小 RNA，已被提议用于结合和调节靶 RNA（如 microRNA）、切割靶（如短干扰 RNA）或完全缺乏生物学功能。尽管 piRNA 通路蛋白突变体是雄性不育的，但尚未确定任何哺乳动物 piRNA 产生基因座的生物学功能。在这里，我们报告缺乏来自 6 号染色体 ( pi6 )上保守的小鼠粗线期 piRNA 基因座的 piRNA 的雄性产生的精子在获能和卵子受精方面存在缺陷。此外，由pi6 ^-/-父亲产生的杂合胚胎在子宫内表现出降低的活力。分子分析表明pi6piRNA通过切割编码精子功能所需蛋白质的信使RNA来抑制基因表达。pi6还参与了 piRNA-piRNA 前体相互作用的网络，该网络从 10 号染色体上的第二个 piRNA 基因座以及pi6本身开始产生 piRNA。我们的数据确立了粗线期 piRNA 在精子发生和胚胎活力中的直接作用。