RNA-dependent RNA polymerase 6 is required for efficient hpRNA-induced gene silencing in plants

• Published in: Molecules and cells Vol. 35; no. 3; pp. 202 - 209
• Main Authors: Harmoko, Rikno, Fanata, Wahyu Indra Duwi, Yoo, Jae Yong, Ko, Ki Seong, Rim, Yeong Gil, Uddin, Mohammad Nazim, Siswoyo, Tri Agus, Lee, Seung Sik, Kim, Dool Yi, Lee, Sang Yeol, Lee, Kyun Oh
• Format: Journal Article
• Language: English
• Published: Springer Korean Society for Molecular and Cellular Biology 01.03.2013; Korea Society for Molecular and Cellular Biology; 한국분자세포생물학회
• Subjects: Arabidopsis - enzymology; Arabidopsis - genetics; Arabidopsis Proteins - physiology; Biochemistry; Biomedical and Life Sciences; Biomedicine; Biotechnology; Cell Biology; Gene Expression Regulation, Plant; Genes, Plant; Green Fluorescent Proteins - biosynthesis; Green Fluorescent Proteins - genetics; Inverted Repeat Sequences; Life Sciences; Mutation; Phenotype; Research Article; RNA Interference; RNA, Small Interfering - genetics; RNA-Dependent RNA Polymerase - physiology; Seedlings - enzymology; Seedlings - genetics; 생물학; hairpin RNA; RDR6; gene silencing; RNA interference; double-stranded RNA; single-stranded RNA
• ISSN: 1016-8478; 0219-1032
• DOI: 10.1007/s10059-013-2203-2

In plants, transgenes with inverted repeats are used to induce efficient RNA silencing, which is also frequently induced by highly transcribed sense transgenes. RNA silencing induced by sense transgenes is dependent on RNA-dependent RNA polymerase 6 (RDR6), which converts single-stranded (ss) RNA into double-stranded (ds) RNA. By contrast, it has been proposed that RNA silencing induced by self-complementary hairpin RNA (hpRNA) does not require RDR6, because the hpRNA can directly fold back on itself to form dsRNA. However, it is unclear whether RDR6 plays a role in hpRNA-induced RNA silencing by amplifying dsRNA to spread RNA silencing within the plant. To address the efficiency of hpRNA-induced RNA silencing in the presence or absence of RDR6, Wild type (WT, Col-0) and rdr6-11 Arabidopsis thaliana lines expressing green fluorescent protein (GFP) were generated and transformed with a GFP-RNA interference (RNAi) construct. Whereas most GFP-RNAi-transformed WT lines exhibited almost complete silencing of GFP expression in the T1 generation, various levels of GFP expression remained among the GFP-RNAi-transformed rdr6-11 lines. Homozygous expression of GFP-RNAi in the T3 generation was not sufficient to induce complete GFP silencing in several rdr6-11 lines. Our results indicate that RDR6 is required for efficient hpRNA-induced RNA silencing in plants.