Translational regulation by Argonaute protein, MIWI, and poly(A)-binding proteins

聚(A)结合蛋白结合真核生物mRNA的聚(A)尾部，是mRNA代谢的核心参与者，包括mRNA的稳定性、翻译和衰变。我们之前的研究表明，聚(A)结合蛋白PABPC1和PABPC2与睾丸特异性Argonaute蛋白MIWI/PIWIL1相互作用，表明MIWI参与了精子发生过程中的翻译调控。与我们的预期相反，当连接到报告mrna时，MIWI对翻译没有显著影响。此外，在翻译不活跃的mRNP部分中几乎检测不到MIWI。这些结果表明，MIWI至少与翻译抑制无关。我们还利用敲除小鼠阐明了睾丸特异性PABPC2的功能。

Poly(A)-binding protein, which binds poly(A) tail of eukaryotic mRNAs, is a central player of mRNA metabolism, including mRNA stability, translation, and decay. We have previously shown that poly(A)-binding proteins, PABPC1 and PABPC2, interact with a testis-specific Argonaute protein, MIWI/PIWIL1, suggesting that MIWI is involved in translational regulation during spermatogenesis. Contrary to our expectation, MIWI had no significant effects on translation, when tethered to reporter mRNAs. Moreover, MIWI was barely detected in translationally inactive mRNP fractions. These results suggest that MIWI is not implicated in, at least, translational repression. We also elucidated the functionof PABPC2, a testis-specific PABPC, using knock-out mice.