Cucumber mosaic virus 2b protein inhibits RNA silencing pathways in green alga Chlamydomonas reinhardtii
Cucumber mosaic virus 2b protein inhibits RNA silencing pathways in green alga Chlamydomonas reinhardtii
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DOI：
10.1007/s00299-010-0882-0
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发表时间：
2010-09-01
影响因子：
6.2
通讯作者：
Jeong, Won-Joong
中科院分区：
文献类型：
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作者：
Ahn, Joon-Woo;Yin, Chun-Ji;Jeong, Won-Joong
RNA沉默的功能是抑制植物和动物的内源基因表达和抗病毒防御。黄瓜花叶病毒2b（Cucumber mosaic virus 2b，CMV 2b）是高等植物中RNA沉默的抑制因子。在本研究中，我们评估了RNA沉默抑制剂CMV 2b在莱茵衣藻的活性。在转化之前，我们修饰了CMV 2b密码子以增加GC含量，以在C中获得最佳表达。莱因哈德氏菌在表达CMV 2b的Maa 7-IR 44菌株中检测到Maa 7沉默的抑制，表明CMV 2b抑制C.高等植物中的莱茵衣藻。此外，在CMV 2b表达菌株中，miRNA切割靶向的mRNA表达显著更高，但未检测到miRNA积累增加。这些结果表明，在C.莱因哈德氏菌有趣的是，Argonaute 1（AGO 1）和Dicer样1（DCL 1）的表达，由双向启动子调节，在CMV 2b表达菌株中减少，表明CMV 2b可能影响参与RNA沉默途径的转录因子。此外，在CMV 2b表达菌株中检测到AGO 2和AGO 3表达的减少。综上所述，我们的研究结果表明，CMV 2b可以抑制siRNA和miRNA途径，也损害了C.莱因哈德氏菌
The functions of RNA silencing are repression of endogenous gene expression and antiviral defense in plants and animals. Cucumber mosaic virus 2b (CMV2b) is a suppressor of RNA silencing in higher plants. In the present study, we evaluated the RNA silencing suppressor activity of CMV2b in Chlamydomonas reinhardtii. Before transformation, we modified CMV2b codons to increase the GC content for optimal expression in C. reinhardtii. Inhibition of Maa7 silencing was detected in CMV2b-expressing Maa7-IR44 strains, indicating that CMV2b suppressed siRNA pathways in C. reinhardtii as in higher plants. In addition, mRNA expression targeted for cleavage by miRNA was significantly higher in CMV2b-expressing strains, but increased accumulation of miRNA was not detected. These results indicate that the suppression of miRNA pathways is mediated by CMV2b in C. reinhardtii. Interestingly, expression of both Argonaute 1 (AGO1) and Dicer-like 1 (DCL1), regulated by a bidirectional promoter, was reduced in CMV2b-expressing strains, suggesting that CMV2b may affect transcription factors involved in RNA silencing pathways. Furthermore, reduction of AGO2 and AGO3 expression was detected in CMV2b-expressing strains. Taken together, our results demonstrate that CMV2b may suppress both siRNA and miRNA pathways, and also impair AGOs and DCL1 expression in C. reinhardtii.