P-element induced wimpy testis (PIWIs) are crucial guardians of genome integrity, particularly in germ cells. While mammalian PIWIs have been primarily studied in mouse and rat, a homologue for the human PIWIL3 gene is absent in the Muridae family, and hence the unique function of PIWIL3 in germ cells cannot be effectively modeled by mouse knockouts. Herein, we investigated the expression, distribution, and interaction of PIWIL3 in bovine oocytes. We localized PIWIL3 to mitochondria, and demonstrated that PIWIL3 expression is stringently controlled both spatially and temporally before and after fertilization. Moreover, we identified PIWIL3 in a mitochondrial-recruited three-membered complex with Tudor and KH domain-containing protein (TDRKH) and poly(A)-specific ribonuclease-like domain containing 1 (PNLDC1), and demonstrated by mutagenesis that PIWIL3 N-terminal arginines are required for complex assembly. Finally, we sequenced the piRNAs bound to PIWIL3-TDRKH-PNLDC1 and report here that about 50% of these piRNAs map to transposable elements, recapitulating the important role of PIWIL3 in maintaining genome integrity in mammalian oocytes.

中文翻译：

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PIWIL3在哺乳动物卵母细胞中与TDRKH形成复合物。

P元素诱导的imp弱睾丸（PIWI）是基因组完整性的重要守护者，特别是在生殖细胞中。尽管哺乳动物PIWI主要在小鼠和大鼠中进行了研究，但人类PIWIL3的同系物Muridae家族中没有该基因，因此不能通过小鼠基因敲除有效地模拟PIWIL3在生殖细胞中的独特功能。本文中，我们研究了PIWIL3在牛卵母细胞中的表达，分布和相互作用。我们将PIWIL3定位于线粒体，并证明PIWIL3的表达受精前后在空间和时间上均受到严格控制。此外，我们在具有Tudor和含KH结构域的蛋白质（TDRKH）和含1的多聚（A）特异性核糖核酸酶样结构域的线粒体招募的三元复合物中鉴定出PIWIL3，并通过诱变证明PIWIL3 N-复杂装配需要末端精氨酸。最后，我们对与PIWIL3-TDRKH-PNLDC1结合的piRNA进行了测序，并在此报告说，这些piRNA中约有50％映射到转座因子，