scholarly journals Phytohormone abscisic acid control RNA-dependent RNA polymerase 6 gene expression and post-transcriptional gene silencing in rice cells

2007 ◽  
Vol 36 (4) ◽  
pp. 1220-1226 ◽  
Author(s):  
J. H. Yang ◽  
H. H. Seo ◽  
S. J. Han ◽  
E. K. Yoon ◽  
M. S. Yang ◽  
...  
Keyword(s):  
Gene Expression ◽  
Abscisic Acid ◽  
Rna Polymerase ◽  
Gene Silencing ◽  
Transcriptional Gene Silencing ◽  
Rna Dependent Rna Polymerase ◽  
Acid Control ◽  
Post Transcriptional Gene Silencing

scholarly journals In plants, decapping prevents RDR6-dependent production of small interfering RNAs from endogenous mRNAs

2015 ◽  
Author(s):  
Angel Emilio Martínez de Alba ◽  
Ana Moreno ◽  
Marc Gabriel ◽  
Allison C Mallory ◽  
Aurélie Christ ◽  
...  
Keyword(s):  
Quality Control ◽  
Rna Polymerase ◽  
Gene Silencing ◽  
Transcriptional Gene Silencing ◽  
Small Interfering Rnas ◽  
Rna Dependent Rna Polymerase ◽  
P Bodies ◽  
New Class ◽  
Post Transcriptional Gene Silencing ◽  
Rna Quality Control

Cytoplasmic degradation of endogenous RNAs is an integral part of RNA quality control (RQC) and often relies on the removal of the 5’ cap structure and their subsequent 5’ to 3’ degradation in cytoplasmic processing (P-)bodies. In parallel, many eukaryotes degrade exogenous and selected endogenous RNAs through post-transcriptional gene silencing (PTGS). In plants, PTGS depends on small interfering (si)RNAs produced after the conversion of single-stranded RNAs to doublestranded RNAs by the cellular RNA DEPENDENT RNA POLYMERASE 6 (RDR6) in cytoplasmic siRNA-bodies. PTGS and RQC compete for transgene-derived RNAs, but it is unknown whether this competition also occurs for endogenous transcripts. We show that the lethality of decapping mutants is suppressed by impairing RDR6 activity. We establish that upon decapping impairment hundreds of endogenous mRNAs give rise to a new class of rqc-siRNAs, that over-accumulate when RQC processes are impaired, a subset of which depending on RDR6 for their production. We observe that P- and siRNA-bodies often are dynamically juxtaposed, potentially allowing for crosstalk of the two machineries. Our results suggest that the decapping of endogenous RNA limits their entry into the PTGS pathway. We anticipate that the rqc-siRNAs identified in decapping mutants represent a subset of a larger ensemble of endogenous siRNAs.

VEGF Specific siRNAs Act Synergistically with Bortezomib and Steroids in Inhibiting VEGF Gene Expression, Proliferation and Induction of Apoptosis in Multiple Myeloma Cells.

Blood ◽  
2004 ◽  
Vol 104 (11) ◽  
pp. 5266-5266
Author(s):  
Michael Koldehoff ◽  
Nina K. Steckel ◽  
Rudolf Trenschel ◽  
Dietrich W. Beelen ◽  
Ahmet H. Elmaagacli
Keyword(s):  
Gene Expression ◽  
Multiple Myeloma ◽  
Bone Marrow ◽  
Gene Silencing ◽  
Antitumor Agents ◽  
Synergistic Effects ◽  
Transcriptional Gene Silencing ◽  
Vegf Gene ◽  
Post Transcriptional Gene Silencing ◽  
Induction Of Apoptosis

Abstract Multiple myeloma (MM) is a clonal B-cell malignancy characterized by the accumulation of malignant plasma cells within the bone marrow (BM). Vascular endothelial growth factor (VEGF), a glycoprotein produced by normal and neoplastic cells is an important regulator of physiological and pathological angiogenesis. MM cells secrete VEGF, which promotes production of cytokines in bone marrow stromal cells, as well as migration and proliferation of the tumor cells. Inhibition of VEGF activity or disabling the function of its receptors has been shown to inhibit both tumor growth and spread of metastases in a variety of animal tumor models. RNA interference (RNAi) is rapidly being established as a post-transcriptional gene silencing method and holds promise to specifically inhibit gene expression in mammals. Another novel class of antitumor agents is based on the inhibition of the ubiquitin-proteosomal system which represents the major nonlysosomal pathway through which intracellular proteins are degraded in eukaryotic cells. Bortezomib, a reversible proteosome inhibitor, shows remarkable anticancer activity in various malignant cell types, including MM cells that are resistant to conventional therapies. We studied the effect of transfection with small interfering RNA (siRNA) targeting VEGF in MM cells in terms of proliferation, induction of apoptosis, and cell differentiation. Further, we evaluated if the effects of post-transcriptional gene silencing by VEGF specific siRNA can be augmented by bortezomib and/or steroids in the cell line OPM-2. A mean reduction of VEGF gene expression to 38% as determined by real-time PCR was observed with 0.8 ug VEGF siRNA in OPM-2 cells compared to controls (controls were set up to 100%). Simultaneous administration of bortezomib and siRNA was able to reduce VEGF gene expression down to 23% compared to VEGF siRNA alone demonstrating a synergistic effect of combined bortezomib and siRNA treatment. We found a 2.5-fold increase in induced apoptosis in OPM-2 cells subsequent to VEGF siRNA administration but we saw no additional stimulation of apoptosis after combination of VEGF siRNA with bortezomib and/or steroids. Proliferation in OPM-2 cells was strongly inhibited (about 91%) following combination treatment as opposed to only 62% after administration of VEGF siRNA alone. The transfection of VEGF siRNA in OPM-2 cells had no influence on the expression levels of differentiation markers such as CD38, CD138, CD19, CD34, CD45, and CD7AAD. Our findings suggest that synergistic effects of VEGF siRNA with bortezomib and dexamethason may offer new therapeutic options in the treatment of MM.

RNA duplexes in transcriptional regulation

2010 ◽  
Vol 1 (3-4) ◽  
pp. 285-296
Author(s):  
Sanjay Swaminathan ◽  
Chantelle L. Hood ◽  
Kazuo Suzuki ◽  
Anthony D. Kelleher
Keyword(s):  
Gene Expression ◽  
Transcriptional Regulation ◽  
Gene Silencing ◽  
Gene Activation ◽  
Current Status ◽  
Transcriptional Gene Silencing ◽  
Regulatory Pathways ◽  
Rna Molecules ◽  
Post Transcriptional Gene Silencing ◽  
Rna Duplexes

AbstractTranscriptional regulation by small RNA molecules, including small interfering RNA and microRNA, has emerged as an important gene expression modulator. The regulatory pathways controlling gene expression, post-transcriptional gene silencing and transcriptional gene silencing (TGS) have been demonstrated in yeast, plants and more recently in human cells. In this review, we discuss the currents models of transcriptional regulation and the main components of the RNA-induced silencing complex and RNA-induced transcriptional silencing complex machinery, as well as confounding off-target effects and gene activation. We also discuss RNA-mediated TGS within the NF-κB motif of the human immunodeficiency virus type 1 5′ long tandem repeat promoter region and the associated epigenetic modifications. Finally, we outline the current RNA interference (RNAi) delivery methods and describe the current status of human trials investigating potential RNAi therapeutics for several human diseases.

scholarly journals small RNA can move long distances through plant vasculature to influence gene expression in shoot apical meristems

2021 ◽  
Author(s):  
Mark A. A. Minow ◽  
Viktoriya Coneva ◽  
Victoria Lesy ◽  
Max Misyura ◽  
Joseph Colasanti
Keyword(s):  
Gene Expression ◽  
Stem Cells ◽  
Gene Silencing ◽  
Small Rna ◽  
Separate Experiment ◽  
Transcriptional Gene Silencing ◽  
Long Distance ◽  
Regulate Gene Expression ◽  
Post Transcriptional Gene Silencing ◽  
Influence Gene Expression

AbstractIn plants, small RNA (sRNA) can regulate gene expression via post transcriptional gene silencing (PTGS) or through RNA-directed DNA methylation (RdDM) leading to transcriptional gene silencing (TGS). sRNA is mobile throughout the plant, with movement occurring short distances from cell-to-cell as well as long distances through the vasculature via phloem trafficking. The range of long-distance sRNA mediated signaling from the vasculature to the shoot apical meristem (SAM) is not clear. To investigate this, two independent transgenic approaches were used to examine trafficking of phloem-expressed sRNA to the SAM in Arabidopsis thaliana. First, the phloem companion-cell specific promoter SUC2 was used to drive expression of an inverted repeat complementary to FLOWERING LOCUS D (FD), a flowering time regulator expressed exclusively in the SAM. In a separate experiment, the SUC2 promoter was used to express an artificial microRNA (aMiR) designed to target a synthetic CLAVATA3 (CLV3) target in the SAM stem cells. Both systems provide evidence of a phloem-to-SAM sRNA communication axis connecting distal regions of the plant to the stem cells of the SAM, which ultimately gives rise to all shoot tissues, including gametes. Thus, phloem-to-SAM sRNA movement defines an important link between sRNA expressed in distal regions of the plant and the growing shoot. Importantly, phloem-to-SAM sRNA trafficking may allow somatic sRNA to direct SAM RdDM, fixing transient sRNA expression events into stable epigenetic changes.

scholarly journals Viroids as a Tool to Study RNA-Directed DNA Methylation in Plants

Cells ◽  
2021 ◽  
Vol 10 (5) ◽  
pp. 1187
Author(s):  
Michael Wassenegger ◽  
Athanasios Dalakouras
Keyword(s):  
Dna Methylation ◽  
Rna Interference ◽  
Gene Silencing ◽  
Plant Cells ◽  
Transcriptional Gene Silencing ◽  
Rnai Machinery ◽  
Double Stranded Rna ◽  
Post Transcriptional Gene Silencing ◽  
Cumulative Amount

Viroids are plant pathogenic, circular, non-coding, single-stranded RNAs (ssRNAs). Members of the Pospiviroidae family replicate in the nucleus of plant cells through double-stranded RNA (dsRNA) intermediates, thus triggering the host’s RNA interference (RNAi) machinery. In plants, the two RNAi pillars are Post-Transcriptional Gene Silencing (PTGS) and RNA-directed DNA Methylation (RdDM), and the latter has the potential to trigger Transcriptional Gene Silencing (TGS). Over the last three decades, the employment of viroid-based systems has immensely contributed to our understanding of both of these RNAi facets. In this review, we highlight the role of Pospiviroidae in the discovery of RdDM, expound the gradual elucidation through the years of the diverse array of RdDM’s mechanistic details and propose a revised RdDM model based on the cumulative amount of evidence from viroid and non-viroid systems.

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