The SID-1 double-stranded RNA transporter is not required for systemic RNAi in the migratory locust
The SID-1 double-stranded RNA transporter is not required for systemic RNAi in the migratory locust
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DOI：
10.4161/rna.19986
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发表时间：
2012-05-01
期刊：
影响因子：
4.1
通讯作者：
Kang, Le
中科院分区：
文献类型：
--
作者：
Luo, Yuan;Wang, Xianhui;Kang, Le
系统性RNAi，即RNAi效应向最初没有遇到dsRNA触发器的细胞和组织传播，是许多生物体中的一种常见现象。然而，系统性RNAi的潜在机制在很大程度上仍不清楚。在这里，我们研究了蝗虫系统RNAi的特征和可能的机制。我们观察到，蝗虫对广泛表达和组织特异性基因的dsRNA注射都有明显的敏感的系统RNAi反应。只有30pg(dsRNA/mg组织)剂量才能诱导显著的全身性RNAi效应。在蝗虫基因组中仅发现一个SID-1同源基因(LmSID-1)，该基因随发育呈递增表达模式，并在性腺中表达丰富。为了测试LmSID-1在系统RNAi中的作用，我们进行了体外和体内实验。体内实验结果表明，沉默LmSID-1基因并不影响其他基因的RNAi效应。体外实验结果证实，LmSID-1蛋白在果蝇S2细胞中的表达不能促进dsRNA的摄取。因此，这些发现意味着昆虫系统RNAi可能存在不同于线虫或哺乳动物的替代机制。
Systemic RNAi, the spreading of RNAi effects to cells and tissues that have not initially encountered a dsRNA trigger, is a common phenomenon in many organisms. However, the underlying mechanisms of systemic RNAi remain largely unknown. Here, we studied the characteristics and possible mechanisms of systemic RNAi in Locusta migratoria. We observed that the locust has pronounced sensitive systemic RNAi in response to dsRNA injection for both broadly-expressed as well as tissue-specific genes. Only a 30 pg (dsRNA/mg tissues) dose could induce significant systemic RNAi effects. Only one SID-1 ortholog (LmSID-1) was identified in the locust genome, which exhibited a progressively increasing expression pattern with development and its expression was enriched in the gonad. To test the role of LmSID-1 in systemic RNAi, we performed in vitro and in vivo experiments. The results from in vivo experiments showed that silencing of LmSID-1 gene dose not influence RNAi effects of other genes. The results from in vitro experiments confirmed that the expression of the LmSID-1 protein in Drosophila S2 cells could not enhance dsRNA uptake. Thus, these findings imply the existence of alternative mechanisms underlying insect systemic RNAi, which may be different from Caenorhabditis elegans or mammals.