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RNA-Dependent RNA Polymerase 6 Is Required for Efficient hpRNA-Induced Gene Silencing in Plants
RIKNOHARMOKO,이균오,Wahyu Indra Duwi Fanata,유재용,고기성,임영길,엠다나짐우단,Tri Agus Siswoyo,이승식,김둘이,이상열 한국분자세포생물학회 2013 Molecules and cells Vol.35 No.3
In plants, transgenes with inverted repeats are used to in-duce 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 con-verts 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.
Rikno Harmoko,Jae Yong Yoo,Ki Seong Ko,Nirmal Kumar Ramasamy,Bo Young Hwang,Eun Ji Lee,Ho Soo Kim,Kyung Jin Lee,Doo-Byoung Oh,Dool-Yi Kim,Sanghun Lee,Yang Li,Sang Yeol Lee,Kyun Oh Lee 한국당과학회 2016 한국당과학회 학술대회 Vol.2016 No.07
In plants, α1,3-fucosyltransferase (FucT) catalyzes the transfer of fucose from GDP-fucose to asparagine-linked GlcNAc of the N-glycan core in the medial Golgi. To explore the physiological significance of this processing, we isolated two Oryza sativa (rice) mutants (fuct-1 and fuct-2) with loss of FucT function. Biochemical analyses of the N-glycan structure confirmed that α1,3-fucose is missing from the N-glycans of allelic fuct-1 and fuct-2. Compared with the wild-type cv Kitaake, fuct-1 displayed a larger tiller angle, shorter internode and panicle lengths, and decreased grain filling as well as an increase in chalky grains with abnormal shape. The mutant allele fuct-2 gave rise to similar developmental abnormalities, although they were milder than those of fuct-1. Restoration of a normal tiller angle in fuct-1 by complementation demonstrated that the phenotype is caused by the loss of FucT function. Both fuct-1 and fuct-2 plants exhibited reduced gravitropic responses. Expression of the genes involved in tiller and leaf angle control was also affected in the mutants. We demonstrate that reduced basipetal auxin transport and low auxin accumulation at the base of the shoot in fuct-1 account for both the reduced gravitropic response and the increased tiller angle.
Cell cycle arrest mediated by WEE1 is involved in the unfolded protein response in plants
고기성,유재용,Nirmal Kumar Ramasamy,RIKNOHARMOKO,Bích Ngọc Thị Vũ,박지예,이균오 한국식물생명공학회 2018 Plant biotechnology reports Vol.12 No.5
Activation of the unfolded protein response (UPR) in mammalian cells leads to cell cycle arrest at the G1 phase (Thomas et al., J Biol Chem 288:7606–7617, 2013). However, how UPR signaling affects cell cycle arrest remains largely unknown in plants. Here, we examined UPR and endoreduplication in Col-0, wee1, and ER stress sensing-deficient ire1a&b plants during DNA replication and ER stress conditions. We found that WEE1, an essential negative regulator of the cell cycle, is involved in the maintenance of ER homeostasis during genotoxic stress and the ER stress hypersensitivity of ire1a&b is alleviated by loss-of-function mutation in WEE1. WEE1-mediated cell cycle arrest was required for IRE1–bZIP60 pathway activation during ER stress. In contrast, loss-of-function mutation in WEE1 caused increased expression of UPR-related genes during DNA replication stress. WEE1 and IRE1 were required for endoreduplication during DNA replication stress and ER stress, respectively. Taken together, these findings suggest that cell cycle regulation is associated with UPR activation in different manners during ER stress and DNA replication stress in Arabidopsis.