scholarly journals Trigger and suppression of antiviral defenses by grapevine Pinot gris virus (GPGV): novel insights into virus-host interaction

2021 ◽  
Author(s):  
Giulia Tarquini ◽  
Laura Pagliari ◽  
Paolo Ermacora ◽  
Rita Musetti ◽  
Giuseppe Firrao
Keyword(s):  
Rna Silencing ◽  
Infectious Clone ◽  
Transcriptional Gene Silencing ◽  
Antiviral Defense ◽  
Small Interfering Rnas ◽  
Host Interaction ◽  
Post Transcriptional Gene Silencing ◽  
Gene Expression Analyses ◽  
Grapevine Pinot Gris Virus

Grapevine Pinot gris virus (GPGV) is an emerging trichovirus that has been putatively associated with a novel grapevine disease known as grapevine leaf mottling and deformation (GLMD). Yet the role of GPGV in GLMD disease is poorly understood since it has been detected both in symptomatic and symptomless grapevines. We exploited a recently constructed GPGV infectious clone (pRI::GPGV-vir) to induce an antiviral response in Nicotiana benthamiana plants. In silico prediction of virus-derived small interfering RNAs (vsiRNAs) and gene expression analyses revealed the involvement of DCL4, AGO5 and RDR6 genes during GPGV infection, suggesting the activation of the post-transcriptional gene-silencing (PTGS) pathway as a plant antiviral defense. PTGS suppression assays in transgenic N. benthamiana 16c plants revealed the ability of the GPGV coat protein to suppress RNA silencing. This work provides novel insights on the interaction between GPGV and its host, revealing the ability of the virus to trigger and suppress antiviral RNA silencing.

scholarly journals Effects of the Crinivirus Coat Protein–Interacting Plant Protein SAHH on Post-Transcriptional RNA Silencing and Its Suppression

2013 ◽  
Vol 26 (9) ◽  
pp. 1004-1015 ◽  
Author(s):  
M. Carmen Cañizares ◽  
Rosa Lozano-Durán ◽  
Tomás Canto ◽  
Eduardo R. Bejarano ◽  
David M. Bisaro ◽  
...  
Keyword(s):  
Coat Protein ◽  
Rna Silencing ◽  
Rna Degradation ◽  
Plant Viruses ◽  
Plant Protein ◽  
Transcriptional Gene Silencing ◽  
Small Interfering Rnas ◽  
Post Transcriptional Gene Silencing ◽  
Secondary Sirnas ◽  
Tomato Chlorosis Virus

In plants, post-transcriptional gene silencing (PTGS) is a sequence-specific mechanism of RNA degradation induced by double-stranded RNA (dsRNA), which is processed into small interfering RNAs (siRNAs). siRNAs are methylated and, thereby, stabilized by the activity of the S-adenosylmethionine-dependent RNA methyltransferase HEN1. PTGS is amplified by host-encoded RNA-dependent RNA polymerases (RDR), which generate dsRNA that is processed into secondary siRNAs. To counteract this RNA silencing-mediated response of the host, plant viruses express proteins with silencing suppression activity. Here, we report that the coat protein (CP) of crinivirus (family Closteroviridae, genus Crinivirus) Tomato chlorosis virus, a known suppressor of silencing, interacts with S-adenosylhomocysteine hydrolase (SAHH), a plant protein essential for sustaining the methyl cycle and S-adenosylmethionine-dependent methyltransferase activity. Our results show that, by contributing to an increased accumulation of secondary siRNAs generated by the action of RDR6, SAHH enhances local RNA silencing. Although downregulation of SAHH prevents local silencing, it enhances the spread of systemic silencing. Our results also show that SAHH is important in the suppression of local RNA silencing not only by the crinivirus Tomato chlorosis virus CP but also by the multifunctional helper component-proteinase of the potyvirus Potato virus Y.

scholarly journals Functional dissection of the ARGONAUTE7 promoter

2018 ◽  
Author(s):  
J. Steen Hoyer ◽  
Jose L. Pruneda-Paz ◽  
Ghislain Breton ◽  
Mariah A. Hassert ◽  
Emily E. Holcomb ◽  
...  
Keyword(s):  
Binding Sites ◽  
Rna Silencing ◽  
Leaf Shape ◽  
Effector Proteins ◽  
Transcriptional Gene Silencing ◽  
Antiviral Defense ◽  
Post Transcriptional Gene Silencing ◽  
And Function ◽  
Central Effector ◽  
Ranked List

AbstractARGONAUTES are the central effector proteins of RNA silencing which bind target transcripts in a small RNA-guided manner. Arabidopsis thaliana has ten ARGONAUTE (AGO) genes, with specialized roles in RNA-directed DNA methylation, post-transcriptional gene silencing, and antiviral defense. To better understand specialization among AGO genes at the level of transcriptional regulation we tested a library of 1497 transcription factors for binding to the promoters of AGO1, AGO10, and AGO7 using yeast 1-hybrid assays. A ranked list of candidate DNA-binding TFs revealed binding of the AGO7 promoter by a number of proteins in two families: the miR156-regulated SPL family and the miR319-regulated TCP family, both of which have roles in developmental timing and leaf morphology. Possible functions for SPL and TCP binding are unclear: we showed that these binding sites are not required for the polar expression pattern of AGO7, nor for the function of AGO7 in leaf shape. Normal AGO7 transcription levels and function appear to depend instead on an adjacent 124-bp region. Progress in understanding the structure of this promoter may aid efforts to understand how the conserved AGO7-triggered TAS3 pathway functions in timing and polarity.

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.

scholarly journals MicroRNAs in Cardiac Autophagy: Small Molecules and Big Role

Cells ◽  
2018 ◽  
Vol 7 (8) ◽  
pp. 104 ◽  
Author(s):  
Teng Sun ◽  
Meng-Yang Li ◽  
Pei-Feng Li ◽  
Ji-Min Cao
Keyword(s):  
Cardiac Fibrosis ◽  
Heart Diseases ◽  
Critical Role ◽  
Transcriptional Gene Silencing ◽  
Close Link ◽  
Post Transcriptional Gene Silencing ◽  
Evolutionarily Conserved ◽  
Cardiac Disorders ◽  
Cellular Components

Autophagy, which is an evolutionarily conserved process according to the lysosomal degradation of cellular components, plays a critical role in maintaining cell homeostasis. Autophagy and mitochondria autophagy (mitophagy) contribute to the preservation of cardiac homeostasis in physiological settings. However, impaired or excessive autophagy is related to a variety of diseases. Recently, a close link between autophagy and cardiac disorders, including myocardial infarction, cardiac hypertrophy, cardiomyopathy, cardiac fibrosis, and heart failure, has been demonstrated. MicroRNAs (miRNAs) are a class of small non-coding RNAs with a length of approximately 21–22 nucleotides (nt), which are distributed widely in viruses, plants, protists, and animals. They function in mediating the post-transcriptional gene silencing. A growing number of studies have demonstrated that miRNAs regulate cardiac autophagy by suppressing the expression of autophagy-related genes in a targeted manner, which are involved in the pathogenesis of heart diseases. This review summarizes the role of microRNAs in cardiac autophagy and related cardiac disorders. Furthermore, we mainly focused on the autophagy regulation pathways, which consisted of miRNAs and their targeted genes.

scholarly journals Comparative reactions of recombinant papaya ringspot viruses with chimeric coat protein (CP) genes and wild-type viruses on CP-transgenic papaya

2001 ◽  
Vol 82 (11) ◽  
pp. 2827-2836 ◽  
Author(s):  
Chu-Hui Chiang ◽  
Ju-Jung Wang ◽  
Fuh-Jyh Jan ◽  
Shyi-Dong Yeh ◽  
Dennis Gonsalves
Keyword(s):  
Coat Protein ◽  
Sequence Similarity ◽  
Transcriptional Gene Silencing ◽  
Papaya Ringspot Virus ◽  
Wild Type ◽  
Coding Region ◽  
Transgenic Papaya ◽  
Cp Gene ◽  
Post Transcriptional Gene Silencing

Transgenic papaya cultivars SunUp and Rainbow express the coat protein (CP) gene of the mild mutant of papaya ringspot virus (PRSV) HA. Both cultivars are resistant to PRSV HA and other Hawaii isolates through homology-dependent resistance via post-transcriptional gene silencing. However, Rainbow, which is hemizygous for the CP gene, is susceptible to PRSV isolates from outside Hawaii, while the CP-homozygous SunUp is resistant to most isolates but susceptible to the YK isolate from Taiwan. To investigate the role of CP sequence similarity in overcoming the resistance of Rainbow, PRSV HA recombinants with various CP segments of the YK isolate were constructed and evaluated on Rainbow, SunUp and non-transgenic papaya. Non-transgenic papaya were severely infected by all recombinants, but Rainbow plants developed a variety of symptoms. On Rainbow, a recombinant with the entire CP gene of YK caused severe symptoms, while recombinants with only partial YK CP sequences produced a range of milder symptoms. Interestingly, a recombinant with a YK segment from the 5′ region of the CP gene caused very mild, transient symptoms, whereas recombinants with YK segments from the middle and 3′ parts of the CP gene caused prominent and lasting symptoms. SunUp was resistant to all but two recombinants, which contained the entire CP gene or the central and 3′-end regions of the CP gene and the 3′ non-coding region of YK, and the resulting symptoms were mild. It is concluded that the position of the heterologous sequences in the recombinants influences their pathogenicity on Rainbow.

scholarly journals An atypical class of non-coding small RNAs produced in rice leaves upon bacterial infection

2021 ◽  
Author(s):  
Ganna Reshetnyak ◽  
Jonathan M. Jacobs ◽  
Florence Auguy ◽  
Coline Sciallano ◽  
Lisa Claude ◽  
...  
Keyword(s):  
Gene Silencing ◽  
Stress Responses ◽  
Small Rnas ◽  
Early Stage ◽  
Kinase Domain ◽  
Transcriptional Gene Silencing ◽  
Small Interfering Rnas ◽  
Post Transcriptional Gene Silencing ◽  
Virulent Strains ◽  
Microbe Interactions

ABSTRACTNon-coding small RNAs (sRNA) act as mediators of gene silencing and regulate plant growth, development and stress responses. Early insights into plant sRNAs established a role in antiviral defense and they are now extensively studied across plant-microbe interactions. Here, sRNA sequencing discovered a class of sRNA in rice (Oryza sativa) specifically associated with foliar diseases caused by Xanthomonas oryzae bacteria. Xanthomonas-induced small RNAs (xisRNAs) loci were distinctively upregulated in response to diverse virulent strains at an early stage of infection producing a single duplex of 20-22nt sRNAs. xisRNAs production was dependent on the Type III secretion system, a major bacterial virulence factor for host colonization. xisRNA loci overlap with annotated transcripts sequences often encoding protein kinase domain proteins. A number of the corresponding rice cis-genes have documented functions in immune signaling and some xisRNA loci coincide with the coding sequence of a conserved kinase motif. xisRNAs exhibit features of small interfering RNAs and their biosynthesis depend on canonical components OsDCL1 and OsHEN1. xisRNA induction possibly mediates post-transcriptional gene silencing but they do not broadly suppress cis-genes expression on the basis of mRNA-seq data. Overall, our results identify a group of unusual sRNAs with a potential role in plant-microbe interactions.

Role of inverted DNA repeats in transcriptional and post-transcriptional gene silencing

2000 ◽  
pp. 123-140 ◽  
Author(s):  
Mariëlle W. M. Muskens ◽  
Adriënne P. A. Vissers ◽  
Joseph N. M. Mol ◽  
Jan M. Kooter
Keyword(s):  
Gene Silencing ◽  
Transcriptional Gene Silencing ◽  
Dna Repeats ◽  
Post Transcriptional Gene Silencing

scholarly journals MicroRNAs as Emerging Regulators of Signaling in the Tumor Microenvironment

Cancers ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 911 ◽  
Author(s):  
Shahzad Nawaz Syed ◽  
Bernhard Brüne
Keyword(s):  
Tumor Microenvironment ◽  
Signaling Pathways ◽  
Target Identification ◽  
Cancer Therapeutics ◽  
Protein Translation ◽  
Transcriptional Gene Silencing ◽  
Post Transcriptional Gene Silencing ◽  
Cancer Initiation ◽  
Regulate Protein

A myriad of signaling molecules in a heuristic network of the tumor microenvironment (TME) pose a challenge and an opportunity for novel therapeutic target identification in human cancers. MicroRNAs (miRs), due to their ability to affect signaling pathways at various levels, take a prominent space in the quest of novel cancer therapeutics. The role of miRs in cancer initiation, progression, as well as in chemoresistance, is being increasingly investigated. The canonical function of miRs is to target mRNAs for post-transcriptional gene silencing, which has a great implication in first-order regulation of signaling pathways. However, several reports suggest that miRs also perform non-canonical functions, partly due to their characteristic non-coding small RNA nature. Examples emerge when they act as ligands for toll-like receptors or perform second-order functions, e.g., to regulate protein translation and interactions. This review is a compendium of recent advancements in understanding the role of miRs in cancer signaling and focuses on the role of miRs as novel regulators of the signaling pathway in the TME.

scholarly journals FIERY1 promotes microRNA accumulation by suppressing rRNA-derived small interfering RNAs in Arabidopsis

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Chenjiang You ◽  
Wenrong He ◽  
Runlai Hang ◽  
Cuiju Zhang ◽  
Xiaofeng Cao ◽  
...  
Keyword(s):  
Rna Degradation ◽  
Transcriptional Gene Silencing ◽  
Rrna Processing ◽  
Small Interfering Rnas ◽  
Post Transcriptional Gene Silencing ◽  
Processing Defects ◽  
And Function ◽  
Mirna Abundance ◽  
Unknown Link

Abstract Plant microRNAs (miRNAs) associate with ARGONAUTE1 (AGO1) to direct post-transcriptional gene silencing and regulate numerous biological processes. Although AGO1 predominantly binds miRNAs in vivo, it also associates with endogenous small interfering RNAs (siRNAs). It is unclear whether the miRNA/siRNA balance affects miRNA activities. Here we report that FIERY1 (FRY1), which is involved in 5′−3′ RNA degradation, regulates miRNA abundance and function by suppressing the biogenesis of ribosomal RNA-derived siRNAs (risiRNAs). In mutants of FRY1 and the nuclear 5′−3′ exonuclease genes XRN2 and XRN3, we find that a large number of 21-nt risiRNAs are generated through an endogenous siRNA biogenesis pathway. The production of risiRNAs correlates with pre-rRNA processing defects in these mutants. We also show that these risiRNAs are loaded into AGO1, causing reduced loading of miRNAs. This study reveals a previously unknown link between rRNA processing and miRNA accumulation.

scholarly journals The potential role of epigenetic modifications in the heritability of multiple sclerosis

2014 ◽  
Vol 20 (2) ◽  
pp. 135-140 ◽  
Author(s):  
Yuan Zhou ◽  
Steve Simpson ◽  
Adele F Holloway ◽  
Jac Charlesworth ◽  
Ingrid van der Mei ◽  
...  
Keyword(s):  
Multiple Sclerosis ◽  
Potential Role ◽  
Transcriptional Gene Silencing ◽  
Epigenetic Changes ◽  
Missing Heritability ◽  
Significant Component ◽  
Post Transcriptional Gene Silencing ◽  
Genetic And Environmental Factors ◽  
Ms Pathogenesis

It is now well established that both genetic and environmental factors contribute to and interact in the development of multiple sclerosis (MS). However, the currently described causal genetic variants do not explain the majority of the heritability of MS, resulting in ‘missing heritability’. Epigenetic mechanisms, which principally include DNA methylation, histone modifications and microRNA-mediated post-transcriptional gene silencing, may contribute a significant component of this missing heritability. As the development of MS is a dynamic process potentially starting with inflammation, then demyelination, remyelination and neurodegeneration, we have reviewed the dynamic epigenetic changes in these aspects of MS pathogenesis and describe how environmental risk factors may interact with epigenetic changes to manifest in disease.

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