Modulation of Ago2 Loading by Cyclophilin 40 Endows a Unique Repertoire of Functional miRNAs during Sperm Maturation in Drosophila
Modulation of Ago2 Loading by Cyclophilin 40 Endows a Unique Repertoire of Functional miRNAs during Sperm Maturation in Drosophila
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DOI：
10.1016/j.celrep.2020.108380
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发表时间：
2020-11-10
期刊：
影响因子：
8.8
通讯作者：
Kai, Toshie
中科院分区：
文献类型：
--
作者：
Iki, Taichiro;Takami, Moe;Kai, Toshie
在基因沉默中，Hsp 90分子伴侣机制协助Argonaute（Ago）结合和解旋沉默小RNA（sRNA）双链体。这使得能够形成效应子RNA诱导的沉默复合物（RISC），其通常显示货物偏好。因此，在果蝇中，微小RNA（miRNA）和小干扰RNA（siRNA）分别被差异分选为Ago 1-RISC和Ago 2-RISC。在这里，我们确定苍蝇Cy-clophilin 40（Cyp 40）作为睾丸专门的热休克蛋白90辅伴侣必不可少的精子发生和调节Ago 2-RISC的形成。我们发现睾丸独特的Ago分选和链选择机制在Ago 2上积累了一组独特的miRNA。Cyp 40通过Hsp 90与Ago 2在体外相互作用，并在体内选择性地促进Ago 2结合的miRNAs而不是内源性siRNA的建立。此外，Cyp 40依赖性Ago 2分选的miRNA之一是晚期精子发生所需的，揭示了非常规但保守的果蝇miRNA-Ago 2分选途径的生理相关性。总的来说，这些结果确定RISC的调节作用的热休克蛋白90机制，更一般地说，突出了组织特异性的适应sRNA途径，通过伴侣多样化。
In gene silencing, Hsp90 chaperone machinery assists Argonaute (Ago) binding and unwinding of silencing small RNA (sRNA) duplexes. This enables the formation of effector RNA-induced silencing complex (RISC) that often displays cargo preferences. Hence, in Drosophila, microRNAs (miRNAs) and small-interfering RNAs (siRNAs) are differentially sorted into Agol -RISC and Ago2-RISC, respectively. Here, we identify fly Cy-clophilin 40 (Cyp40) as a testis-specialized Hsp90 co-chaperone essential for spermatogenesis and for modulating Ago2-RISC formation. We show that testis-distinctive Ago-sorting and strand-selection mechanisms accumulate a unique set of miRNAs on Ago2. Cyp40 interacts with duplex-incorporating Ago2 through Hsp90 in vitro and selectively promotes the build-up of Ago2-bound miRNAs, but not endogenous siRNAs, in vivo. Moreover, one of Cyp40-dependent Ago2-sorted miRNAs is required for late spermatogenesis, unraveling the physiological relevance of the unconventional yet conserved Drosophila miRNA-Ago2 sorting pathway. Collectively, these results identify RISC-regulatory roles for Hsp90 machinery and, more generally, highlight the tissue-specific adaptation of sRNA pathways through chaperone diversification.