• Title, Summary, Keyword: RNA interference

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Long Double-stranded RNA Induces Sequence-specific RNA Interference and Type I Interferon Responses in Rock Bream (Oplegnathus fasciatus)

  • Zenke, Kosuke;Kim, Ki-Hong
    • Fisheries and aquatic sciences
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    • v.13 no.1
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    • pp.56-62
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    • 2010
  • To determine whether long double-stranded RNA (dsRNA) induces RNA interference and type I interferon (IFN) responses in fish, long dsRNAs encoding enhanced green fluorescent protein (EGFP), GFPuv, and polyinosinic-polycytidylic acid sequences were co-injected with an EGFP expressing plasmid, into rock bream (Oplegnathus fasciatus). We investigated the EGFP mRNA and protein levels, and the transcriptional responses of dsRNA-dependent protein kinase and Mx1 genes. Long dsRNAs were strong inducers of a type I IFN response in rock bream, resulting in nonspecific suppression of exogenous gene expression. Furthermore, sequence-specific knockdown of exogenous gene expression at the mRNA level was detected at an early phase (24 h). These results suggested that long dsRNA may inhibit exogenous gene expression through an early mRNA interference response and a later type I IFN response in fish.

Interference of EGFP RNA in Human NT-2/D1 Cell Lines Using Human U6 Promoter-based siRNA PCR Products

  • Kwak, Young-Don;Sugaya, Kiminobu
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.11 no.3
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    • pp.273-276
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    • 2006
  • RNA interference (RNAi), a process of sequence-specific gene suppression, has been known as a natural gene regulatory mechanism in a wide range of lower organisms. Recently, we have reported that a transfection of human U6 promoter (hU6) driven hairpin small-interference RNA (siRNA) plasmid specifically knocks down the target gene by post-transcriptional gene silencing in mammalian cells. Here we report that transfection of polymerase chain reaction (PCR) products, containing human U6 promoter with hairpin siRNA, knocks down the target gene expression in human teratocarcinoma NT-2/D1 cells. Moreover, we showed 3' end termination sequence, 5 Ts, is not critical elements for knocking down in PCR-based siRNA system. Therefore, the PCR-based siRNA system is a promising tool not only for the screening but also to temporally regulate gene expression in the human progenitor cells.

RNA Interference in C. elegans: History, Application, and Perspectives

  • Min, Kyoeng-Woo;Lee, Jun-Ho
    • Animal cells and systems
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    • v.11 no.2
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    • pp.99-104
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    • 2007
  • RNA interference (RNAi) is the phenomenon of gene silencing by double-stranded RNA (dsRNA) at transcriptional and post-transcriptional levels in a sequence-specific manner. Reverse genetic approaches using RNA interference (RNAi) have become a major tool for biological researches since its discovery in the nematode Caenorhabditis elegans. In this review, we overview how the RNAi phenomenon was discovered and how the underlying mechanism has been elucidated. We also describe and discuss how RNAi experiments can be performed and how RNAi can be used for genetic studies.

Influence of Expression Plasmid of Connective Tissue Growth Factor and Tissue Inhibitor of Metalloproteinase-1 shRNA on Hepatic Precancerous Fibrosis in Rats

  • Zhang, Qun;Shu, Fu-li;Jiang, Yu-Feng;Huang, Xin-En
    • Asian Pacific Journal of Cancer Prevention
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    • v.16 no.16
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    • pp.7205-7210
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    • 2015
  • Background: In this study, influence caused by expression plasmids of connective tissue growth factor (CTGF) and tissue inhibitor of metalloproteinase-1 (TIMP-1) short hairpin RNA (shRNA) on mRNA expression of CTGF,TIMP-1,procol-${\alpha}1$ and PCIII in hepatic tissue with hepatic fibrosis, a precancerous condition, in rats is analyzed. Materials and Methods: To screen and construct shRNA expression plasimid which effectively interferes RNA targets of CTGF and TIMP-1 in rats. 50 cleaning Wistar male rats are allocated randomly at 5 different groups after precancerous fibrosis models and then injection of shRNA expression plasimids. Plasmid psiRNA-GFP-Com (CTGF and TIMP-1 included), psiRNA-GFP-CTGF, psiRNA-GFP-TIMP-1 and psiRNA-DUO-GFPzeo of blank plasmid are injected at group A, B, C and D, respectively, and as model control group that none plasimid is injected at group E. In 2 weeks after last injection, to hepatic tissue at different groups, protein expression of CTGF, TIMP-1, procol-${\alpha}1$ and PC III is tested by immunohistochemical method and,mRNA expression of CTGF,TIMP-1,procol-${\alpha}1$ and PCIII is measured by real-time PCR. One-way ANOVA is used to comparison between-groups. Results: Compared with model group, there is no obvious difference of mRNA expression among CTGF,TIMP-1,procol-${\alpha}1$, PC III and of protein expression among CTGF, TIMP-1, procol-${\alpha}1$, PC III in hepatic tissue at group injected with blank plasmid. Expression quantity of mRNA of CTGF, TIMP-1, procol-${\alpha}1$ and PCIII at group A, B and C decreases, protein expression of CTGF, TIMP-1, procol-${\alpha}1$, PC III in hepatic tissue is lower, where the inhibition of combination RNA interference group (group A) on procol-${\alpha}1$ mRNA transcription and procol-${\alpha}1$ protein expression is superior to that of single interference group (group B and C) (P<0.01 or P<0.05). Conclusions: RNA interference on CTGF and/or TIMP-1 is obviously a inhibiting factor for mRNA and protein expression of CTGF, TIMP-1, procol-${\alpha}1$ and PCIII. Combination RNA interference on genes of CTGF and TIMP-1 is superior to that of single RNA interference, and this could be a contribution for prevention of precancerous condition.

Suppression of CDK2 expression by siRNA induces cell cycle arrest and cell proliferation inhibition in human cancer cells

  • Long, Xiang-E.;Gong, Zhao-Hui;Pan, Lin;Zhong, Zhi-Wei;Le, Yan-Ping;Liu, Qiong;Guo, Jun-Ming;Zhong, Jiu-Chang
    • BMB Reports
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    • v.43 no.4
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    • pp.291-296
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    • 2010
  • Cyclin-dependent kinase 2 (CDK2) is a member of serine/threonine protein kinases, which initiates the principal transitions of the eukaryotic cell cycle and is a promising target for cancer therapy. The present study was designed to inhibit cdk2 gene expression to induce cell cycle arrest and cell proliferation suppression. Here, we constructed a series of RNA interference (RNAi) plasmids which can successfully express small interference RNA (siRNA) in the transfected human cells. The results showed that the RNAi plasmids containing the coding sequences for siRNAs down-regulated the cdk2 gene expression in human cancer cells at the mRNA and the protein levels. Furthermore, we found that the cell cycle was arrested at G0G1 phases and the cell proliferation was inhibited by different siRNAs. These results demonstrate that suppression of CDK2 activity by RNAi may be an effective strategy for gene therapy in human cancers.

Mobile transposon-like element, clone MTi7: Finding its role(s) by RNA interference (Mobile transposon-like element, clone MTi7:RNA interference를 이용한 역할 규명)

  • Park, Chang-Eun;Shin, Mi-Ra;Jeon, Eun-Hyun;Cho, Sung-Won;Lee, Sook-Hwan;Kim, Kyung-Jin;Kim, Nam-Hyung;Lee, Kyung-Ah
    • Clinical and Experimental Reproductive Medicine
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    • v.30 no.4
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    • pp.299-307
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    • 2003
  • Objectives: The present study was conducted to evaluate the mobile transposon-like element, clone MTi7 (MTi7) expression in the mouse ovary and to determine its role(s) in the mouse oocytes by RNA interference (RNAi). Methods: MTi7 mRNA expression was localized by in situ hybridization in day5 and adult ovaries. Double stranded RNA (dsRNA) was prepared for c-mos, a gene with known function as control, and the MTi7. Each dsRNA was microinjected into the germinal vesicle (GV) stage oocytes then oocyte maturation and intracellular changes were evaluated. Results: In situ hybridization analysis revealed that MTi7 mRNA localized to the oocyte cytoplasm from primordial to preovulatory follicles. After dsRNA injection, we found 43-54% GV arrest of microinjected GV oocytes with 68%-90% decrease in targeted c-mos or MTi7 mRNA. Conclusions: This is the first report of the oocyte-specific expression of the MTi7 mRNA. From results of RNAi for MTi7, we concluded that the MTi7 is involved in the germinal vesicle breakdown in GV oocytes, and MTi7 may be implicated with c-mos for its function. We report here that RNAi provides an outstanding approach to study the function of a gene with unknown functions.

Simultaneous and Systemic Knock-down of Big Defensin 1 and 2 gene Expression in the Pacific Oyster Crassostrea gigas using Long Double-stranded RNA-mediated RNA Interference

  • Jee, Bo Young;Kim, Min Sun;Cho, Mi Young;Lee, Soon Jeong;Park, Myung Ae;Kim, Jin Woo;Choi, Seung Hyuk;Jeong, Hyun Do;Kim, Ki Hong
    • Fisheries and aquatic sciences
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    • v.17 no.3
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    • pp.377-380
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    • 2014
  • RNA interference (RNAi)-mediated transcriptional knock-down of Crassostrea gigas big defensin 1 and 2 genes (Cg-BigDef1 and Cg-BigDef2) was investigated. The cDNA sequences of Cg-BigDef1 and Cg-BigDef2 were identical, excluding an additional fragment of 20 nucleotides in Cg-BigDef1; thus, a long double-stranded RNA (dsRNA) targeting the mRNA of Cg-BigDef2 effectively downregulated both Cg-BigDef2 and Cg-BigDef1. In addition, long dsRNA targeting green fluorescent protein (GFP) did not affect transcription of the two big defensin genes. These results suggest that the transcriptional downregulation of Cg-BigDef1 and Cg-BigDef2 was mediated by sequence-specific RNA interference (RNAi). Despite injection of long dsRNA targeting Cg-BigDef2 into only the adductor muscle, knock-down of Cg-BigDef1 and Cg-BigDef2 was observed in the adductor muscle, hemocytes, mantle, and gills, suggestive of systemic spread of RNAi in C. gigas. Furthermore, the inhibitory effect of dsRNA persisted until 72 h post-injection, indicative of a long-lasting RNAi-mediated knock-down of target genes.

Establishment and Characterization of MTDH Knockdown by Artificial Micro RNA Interference - Functions as a Potential Tumor Suppressor in Breast Cancer

  • Wang, Song;Shu, Jie-Zhi;Cai, Yi;Bao, Zheng;Liang, Qing-Mo
    • Asian Pacific Journal of Cancer Prevention
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    • v.13 no.6
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    • pp.2813-2818
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    • 2012
  • Background: Considerable evidence suggests that metadherin (MTDH) is a potentially crucial mediator of tumor malignancy and an important therapeutic target for simultaneously enhancing chemotherapy efficacy and reducing metastasis risk. Inhibition of MTDH expression by RNA interference has been shown in several previous research, but silencing MTDH expression by microRNA (miRNA) interference in breast cancer has not been established. In the present study, we investigated the role of MTDH-miRNA in down-regulation of proliferation, motility and migration of breast carcinoma cells. Methods: Expression vectors of recombinant plasmids expressing artificial MTDH miRNA were constructed and transfected to knockdown MTDH expression in MDA-MB-231 breast cancer cells. Expression of MTDH mRNA and protein was detected by RT-PCR and Western blot, respectively. MTT assays were conducted to determine proliferation, and wound healing assays and transwell migration experiments for cell motility and migration. Results: Transfection of recombinant a plasmid of pcDNA-MTDH-miR-4 significantly suppressed the MTDH mRNA and protein levels more than 69% in MDA-MB-231 breast cancer cells. This knockdown significantly inhibited proliferation, motility and migration as compared with controls. Conclusions: MTDH-miRNA may play an important role in down-regulating proliferation, motility and migration in breast cancer cells, and should be considered as a potential small molecule inhibitor therapeutic targeting strategy for the future.

RNA Interference to Prevent Bombyx mori Nuclear Polyhedrosis Virus Infection in Vivo

  • Hu Zhigang;Chen Keping;Gao Lu;Yao Qin
    • International Journal of Industrial Entomology
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    • v.12 no.1
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    • pp.15-19
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    • 2006
  • RNA interference has been used as a powerful tool in preventing virus proliferation in many species. In this study, we injected the dsRNA in vitro transcripts into Bombyx mori to investigate the resistance to B. mori nuclear polyhedrosis virus (BmNPV). Through vivisectional observation and real-time quantities PCR analysis, we found that these dsRNA can prevent the BmNPV to a certain extent, and delay the viruses' proliferation.

Inhibition of Herpesvirus-6B RNA Replication by Short Interference RNAs

  • Yoon, Jong-Sub;Kim, Sun-Hwa;Shin, Min-Chul;Lee, Dong-Gun;Hong, Seong-Karp;Jung, Yong-Tae;Khang, In-Gu;Shin, Wan-Shik;Kim, Chun-Choo;Paik, Soon-Young
    • BMB Reports
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    • v.37 no.3
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    • pp.383-385
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    • 2004
  • RNA interference (RNAi) is a process of sequence-specific gene silencing, which is initiated by double-stranded RNA (dsRNA). RNAi may also serve as an antiviral system in vertebrates. This study describes the inhibition of herpesvirus-6B (HHV-6B) replication by short interference RNAs (siRNAs) that are targeted to the U38 sequence that encodes DNA polymerase. When virus-infected SupT1 cells were treated by siRNA, these cells blocked the cytopathic effect (CPE) and detected the HHV-6B antibody-negative in indirect immunofluorescence assays (IFA). Our result suggests that RNAi can efficiently block Herpesvirus-6B replication.