Tdrkh is essential for spermatogenesis and participates in primary piRNA biogenesis in the germline
Tdrkh is essential for spermatogenesis and participates in primary piRNA biogenesis in the germline
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DOI：
10.1038/emboj.2013.121
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发表时间：
2013-07-03
期刊：
影响因子：
11.4
通讯作者：
Lin, Haifan
中科院分区：
文献类型：
--
作者：
Saxe, Jonathan P.;Chen, Mengjie;Lin, Haifan
Piwi蛋白和Piwi相互作用RNA（piRNA）抑制转座，调节翻译，并指导生殖系中的表观遗传编程。在这里，我们表明，一个进化上保守的Tudor和KH结构域的蛋白质，Tdrkh（又名。Tdrd 2）是精子发生所需的，并参与皮尔纳生物发生。Tdrkh通过Miwi和Miwi 2中的对称二甲基化精氨酸残基与Miwi和Miwi 2配对。Tdrkh是一种线粒体蛋白，通常与pi体和piP体并列，并且是Tdrd 1细胞质定位和Miwi 2核定位所需的。Tdrkh突变体在偶线期显示减数分裂停滞，减弱Line 1 DNA的甲基化，并上调Line 1 RNA和蛋白质，而不诱导细胞凋亡。此外，Tdrkh突变体具有严重降低的成熟piRNA水平，但积累了不同的含1 'U、2' O-甲基化的31-37 nt RNA群体，其在很大程度上补充了缺失的成熟piRNA。我们的结果表明，主要的皮尔纳生物合成途径涉及31-37 nt中间体的3 '-> 5'加工，并且Tdrkh促进皮尔纳生物合成的这一最后步骤，但不促进乒乓循环。这些结果阐明了初级皮尔纳生物发生的机制，这是一个明显缺乏信息的领域。
Piwi proteins and Piwi-interacting RNAs (piRNAs) repress transposition, regulate translation, and guide epigenetic programming in the germline. Here, we show that an evolutionarily conserved Tudor and KH domain-containing protein, Tdrkh (a.k.a. Tdrd2), is required for spermatogenesis and involved in piRNA biogenesis. Tdrkh partners with Miwi and Miwi2 via symmetrically dimethylated arginine residues in Miwi and Miwi2. Tdrkh is a mitochondrial protein often juxtaposed to pi-bodies and piP-bodies and is required for Tdrd1 cytoplasmic localization and Miwi2 nuclear localization. Tdrkh mutants display meiotic arrest at the zygotene stage, attenuate methylation of Line1 DNA, and upregulate Line1 RNA and protein, without inducing apoptosis. Furthermore, Tdrkh mutants have severely reduced levels of mature piRNAs but accumulate a distinct population of 1'U-containing, 2'O-methylated 31-37 nt RNAs that largely complement the missing mature piRNAs. Our results demonstrate that the primary piRNA biogenesis pathway involves 3'-> 5' processing of 31-37 nt intermediates and that Tdrkh promotes this final step of piRNA biogenesis but not the ping-pong cycle. These results shed light on mechanisms underlying primary piRNA biogenesis, an area in which information is conspicuously absent.