A Small-RNA-Mediated Feedback Loop Maintains Proper Levels of 22G-RNAs in C. elegans. A Small-RNA-Mediated Feedback Loop Maintains Proper Levels of 22G-RNAs in C. elegans

ERI-6/7 is a negative regulator of exogenous RNAi, however the function of SOSI-1 has never previously been characterized. We noticed that expression of sosi-1 and eri-6/7 are mutually exclusive. Due to its genomic locus being nested within the eri-6 locus, we hypothesized that sosi-1 could be acting as a regulator of ERI-6/7 function by disrupting eri-6/7 expression upon sensing changes in the production of MUT-16-dependent 22G siRNAs. Our data confirms that expression of the sosi-1 mRNA is regulated by MUT-16-dependent 22G siRNAs. In addition, we show here that the expression of the eri-6 and eri-7 pre-mRNAs, and thus the eri-6/7 trans-spliced mRNA, are mis-regulated upon loss of sosi-1-targeting and eri-6[e-f]-targeting MUT-16-dependent 22G siRNAs, suggesting that sosi-1 and eri-6[e-f] act as a feedback sensor for small RNA function. Overall design: 24 mRNA-seq libraries and 30 small RNA-seq libraries were generated and analyzed. Each genotype per condition were generated in triplicate.

ERI-6/7是外源RNA干扰（exogenous RNAi）的负调控因子，但此前尚未对SOSI-1的功能开展任何表征研究。我们观察到，sosi-1与eri-6/7的表达呈现互斥模式。鉴于sosi-1的基因组位点嵌套于eri-6基因组位点内部，我们提出假说：SOSI-1可通过在感知依赖MUT-16的22G小干扰RNA（22G siRNAs）生成变化时，干扰eri-6/7的表达，从而调控ERI-6/7的功能。本研究数据证实，sosi-1信使RNA（mRNA）的表达受依赖MUT-16的22G小干扰RNA调控。此外，本研究发现，当靶向sosi-1与靶向eri-6[e-f]的依赖MUT-16的22G小干扰RNA缺失时，eri-6与eri-7的前体信使RNA（pre-mRNA）以及由此产生的eri-6/7反式剪接信使RNA的表达均出现失调，这表明sosi-1与eri-6[e-f]可作为小RNA功能的反馈感受器。实验整体设计：共构建并分析了24个信使RNA测序（mRNA-seq）文库与30个小RNA测序（small RNA-seq）文库；每种条件下的各基因型均设置3次生物学重复。