scholarly journals Salient Genetic Notes on Small-RNAs and their Applications in Agricultural Biotechnology

2020 ◽  
pp. 1-17
Author(s):  
Samuel Amiteye
Keyword(s):  
Gene Regulation ◽  
Small Rna ◽  
Small Rnas ◽  
Small Interfering Rna ◽  
Crop Improvement ◽  
Regulation Of Gene Expression ◽  
Healthy Plant ◽  
Biological Processes ◽  
Protein Coding ◽  
Interfering Rna

Small-RNAs are 20 to 27 nucleotides long non-protein-coding RNAs that act on either DNA or RNA to effect the regulation of gene expression. Small-RNAs are key in genetic and epigenetic regulation of diverse biological processes and pathways in response to biotic and abiotic environmental stresses. The gene regulatory functions of small-RNA molecules enhance healthy plant growth and normal development by controlling biological processes such as flowering programming, fruit development, disease and pests resistance. Small-RNAs comprise mainly microRNA and small interfering RNA species. MicroRNAs have been proven to primarily engage in posttranscriptional gene regulation while small interfering RNA have been implicated mainly in transcriptional gene regulation. This review covers the recent advancements in small-RNA research in plants, with emphasis on particularly microRNAs and small interfering RNA biogenesis, biological functions and their relevance in the regulation of traits of agronomic importance in plants. Also discussed extensively is the potential biotechnological applications of these small-RNAs for crop improvement.

scholarly journals Molecular mechanisms of Dicer: endonuclease and enzymatic activity

2017 ◽  
Vol 474 (10) ◽  
pp. 1603-1618 ◽  
Author(s):  
Min-Sun Song ◽  
John J. Rossi
Keyword(s):  
Enzymatic Activity ◽  
Small Rna ◽  
Small Rnas ◽  
Small Interfering Rna ◽  
Molecular Mechanisms ◽  
Cellular Processes ◽  
Interfering Rna ◽  
Exogenous Substrates

The enzyme Dicer is best known for its role as a riboendonuclease in the small RNA pathway. In this canonical role, Dicer is a critical regulator of the biogenesis of microRNA and small interfering RNA, as well as a growing number of additional small RNAs derived from various sources. Emerging evidence demonstrates that Dicer's endonuclease role extends beyond the generation of small RNAs; it is also involved in processing additional endogenous and exogenous substrates, and is becoming increasingly implicated in regulating a variety of other cellular processes, outside of its endonuclease function. This review will describe the canonical and newly identified functions of Dicer.

Gene Regulation by Intracellular Delivery and Photodegradation of Nanoparticles Containing Small Interfering RNA

2014 ◽  
Vol 14 (5) ◽  
pp. 626-631 ◽  
Author(s):  
Shuhei Murayama ◽  
Petra Kos ◽  
Kanjiro Miyata ◽  
Kazunori Kataoka ◽  
Ernst Wagner ◽  
...  
Keyword(s):  
Gene Regulation ◽  
Small Interfering Rna ◽  
Intracellular Delivery ◽  
Interfering Rna

scholarly journals Analysis of RDR1/RDR2/RDR6-independent small RNAs in Arabidopsis thaliana improves MIRNA annotations and reveals novel siRNA loci

2017 ◽  
Author(s):  
Seth Polydore ◽  
Michael J. Axtell
Keyword(s):  
Gene Expression ◽  
Arabidopsis Thaliana ◽  
Small Rna ◽  
Small Rnas ◽  
Rna Seq ◽  
Triple Mutant ◽  
Physiological Mechanisms ◽  
Protein Coding ◽  
Regulate Gene Expression ◽  
Rna Biogenesis

SummaryPlant small RNAs regulate key physiological mechanisms through post-transcriptional and transcriptional silencing of gene expression. sRNAs fall into two major categories: those that are reliant on RNA Dependent RNA Polymerases (RDRs) for biogenesis and those that aren’t. Known RDR-dependent sRNAs include phased and repeat-associated short interfering RNAs, while known RDR-independent sRNAs are primarily microRNAs and other hairpin-derived sRNAs. In this study, we produced and analyzed small RNA-seq libraries from rdr1/rdr2/rdr6 triple mutant plants. Only a small fraction of all sRNA loci were RDR1/RDR2/RDR6-independent; most of these were microRNA loci or associated with predicted hairpin precursors. We found 58 previously annotated microRNA loci that were reliant on RDR1, −2, or −6 function, casting doubt on their classification. We also found 38 RDR1/2/6-independent small RNA loci that are not MIRNAs or otherwise hairpin-derived, and did not fit into other known paradigms for small RNA biogenesis. These 38 small RNA-producing loci have novel biogenesis mechanisms, and are frequently located in the vicinity of protein-coding genes. Altogether, our analysis suggest that these 38 loci represent one or more new types of small RNAs in Arabidopsis thaliana.Significance StatementSmall RNAs regulate gene expression in plants and are produced through a variety of previously-described mechanisms. Here, we examine a set of previously undiscovered small RNA-producing loci that are produced by novel mechanisms.

scholarly journals Comparative Analysis of Biochemical Biases by Ligation- and Template-Switch-Based Small RNA Library Preparation Protocols

2019 ◽  
Vol 65 (12) ◽  
pp. 1581-1591 ◽  
Author(s):  
Morgane Meistertzheim ◽  
Tobias Fehlmann ◽  
Franziska Drews ◽  
Marcello Pirritano ◽  
Gilles Gasparoni ◽  
...  
Keyword(s):  
Small Rna ◽  
Small Rnas ◽  
Regulation Of Gene Expression ◽  
Biochemical Properties ◽  
Library Preparation ◽  
Key Players ◽  
Rna Fragments ◽  
Template Switch ◽  
Small Rna Species ◽  
Small Rna Library

Abstract BACKGROUND Small RNAs are key players in the regulation of gene expression and differentiation. However, many different classes of small RNAs (sRNAs) have been described with distinct biogenesis pathways and, as a result, with different biochemical properties. To analyze sRNAs by deep sequencing, complementary DNA synthesis requires manipulation of the RNA molecule itself. Thus, enzymatic activities during library preparation bias the library content owing to biochemical criteria. METHODS We compared 4 different manipulations of RNA for library preparation: (a) a ligation-based procedure allowing only 5′-mono-phosphorylated RNA to enter the library, (b) a ligation-based procedure allowing additional 5′-triphosphates and Cap structures, (c) a ligation-independent, template-switch-based library preparation, and (d) a template-switch-based library preparation allowing 3′-phosphorylated RNAs to enter the library. RESULTS Our data show large differences between ligation-dependent and ligation-independent libraries in terms of their preference for individual sRNA classes such as microRNAs (miRNAs), Piwi-interacting RNAs (piRNAs), and transfer RNA fragments. Moreover, the miRNA composition is different between both procedures, and more microRNA isoforms (isomiRs) can be identified after pyrophosphatase treatment. piRNAs are enriched in template-switch libraries, and this procedure apparently includes more different RNA species. CONCLUSIONS Our data indicate that miRNAomics from both methods will hardly be comparable. Ligation-based libraries enrich for canonical miRNAs, which thus may be suitable methods for miRNAomics. Template-switch libraries contain increased numbers and different compositions of fragments and long RNAs. Following different interests for other small RNA species, ligation-independent libraries appear to show a more realistic sRNA landscape with lower bias against biochemical modifications.

scholarly journals CCR4-NOT Deadenylates mRNA Associated with RNA-Induced Silencing Complexes in Human Cells

2010 ◽  
Vol 30 (6) ◽  
pp. 1486-1494 ◽  
Author(s):  
Xianghua Piao ◽  
Xue Zhang ◽  
Ligang Wu ◽  
Joel G. Belasco
Keyword(s):  
Small Rna ◽  
Small Interfering Rna ◽  
Inhibitory Effect ◽  
Human Cells ◽  
Predominant Role ◽  
Catalytic Subunits ◽  
Present Evidence ◽  
Mrna Targets ◽  
Protein Components ◽  
Interfering Rna

ABSTRACT MicroRNAs (miRNAs) repress gene expression posttranscriptionally by inhibiting translation and by expediting deadenylation so as to trigger rapid mRNA decay. Their regulatory influence is mediated by the protein components of the RNA-induced silencing complex (RISC), which deliver miRNAs and siRNAs to their mRNA targets. Here, we present evidence that CCR4-NOT is the deadenylase that removes poly(A) from messages destabilized by miRNAs in human cells. Overproducing a mutationally inactivated form of either of the catalytic subunits of this deadenylase (CCR4 or CAF1/POP2) significantly impedes the deadenylation and decay of mRNA targeted by a partially complementary miRNA. The same deadenylase initiates the degradation of “off-target” mRNAs that are bound by an imperfectly complementary siRNA introduced by transfection. The greater inhibitory effect of inactive CAF1 or POP2 (versus inactive CCR4) suggests a predominant role for this catalytic subunit of CCR4-NOT in miRNA- or small interfering RNA (siRNA)-mediated deadenylation. These effects of mi/siRNAs and CCR4-NOT can be fully reproduced by directly tethering RISC to mRNA without the guidance of a small RNA, indicating that the ability of RISC to accelerate deadenylation is independent of RNA base pairing. Despite its importance for mi/siRNA-mediated deadenylation, CCR4-NOT appears not to associate significantly with RISC, as judged by the failure of CAF1 and POP2 to coimmunoprecipitate detectably with either the Ago or TNRC6 subunit of RISC, a finding at odds with deadenylase recruitment as the mechanism by which RISC accelerates poly(A) removal.

Processing of coding and non-coding RNAs in plant development and environmental responses

2020 ◽  
Vol 64 (6) ◽  
pp. 931-945 ◽  
Author(s):  
Fuyan Si ◽  
Xiaofeng Cao ◽  
Xianwei Song ◽  
Xian Deng
Keyword(s):  
Gene Expression ◽  
Plant Development ◽  
Small Rna ◽  
Rna Processing ◽  
Regulation Of Gene Expression ◽  
Rna Transcripts ◽  
Plant Environment ◽  
Non Coding Rnas ◽  
Environmental Responses ◽  
Interfering Rna

Abstract Precursor RNAs undergo extensive processing to become mature RNAs. RNA transcripts are subjected to 5′ capping, 3′-end processing, splicing, and modification; they also form dynamic secondary structures during co-transcriptional and post-transcriptional processing. Like coding RNAs, non-coding RNAs (ncRNAs) undergo extensive processing. For example, secondary small interfering RNA (siRNA) transcripts undergo RNA processing, followed by further cleavage to become mature siRNAs. Transcriptome studies have revealed roles for co-transcriptional and post-transcriptional RNA processing in the regulation of gene expression and the coordination of plant development and plant–environment interactions. In this review, we present the latest progress on RNA processing in gene expression and discuss phased siRNAs (phasiRNAs), a kind of germ cell-specific secondary small RNA (sRNA), focusing on their functions in plant development and environmental responses.

mi-IsoNet: systems-scale microRNA landscape reveals rampant isoform-mediated gain of target interaction diversity and signaling specificity

2021 ◽  
Author(s):  
Li Guo ◽  
Yongsheng Li ◽  
Kara M Cirillo ◽  
Robert A Marick ◽  
Zhe Su ◽  
...  
Keyword(s):  
Gene Regulation ◽  
Small Rna ◽  
Small Rnas ◽  
Regulatory Networks ◽  
Circuit Complexity ◽  
Selective Advantage ◽  
Functional Variation ◽  
Signaling Specificity ◽  
Gene Regulation Network ◽  
Novel Target

Abstract MicroRNA (miRNA) is not a single sequence, but a series of multiple variants (also termed isomiRs) with sequence and expression heterogeneity. Whether and how these isoforms contribute to functional variation and complexity at the systems and network levels remain largely unknown. To explore this question systematically, we comprehensively analyzed the expression of small RNAs and their target sites to interrogate functional variations between novel isomiRs and their canonical miRNA sequences. Our analyses of the pan-cancer landscape of miRNA expression indicate that multiple isomiRs generated from the same miRNA locus often exhibit remarkable variation in their sequence, expression and function. We interrogated abundant and differentially expressed 5′ isomiRs with novel seed sequences via seed shifting and identified many potential novel targets of these 5′ isomiRs that would expand interaction capabilities between small RNAs and mRNAs, rewiring regulatory networks and increasing signaling circuit complexity. Further analyses revealed that some miRNA loci might generate diverse dominant isomiRs that often involved isomiRs with varied seeds and arm-switching, suggesting a selective advantage of multiple isomiRs in regulating gene expression. Finally, experimental validation indicated that isomiRs with shifted seed sequences could regulate novel target mRNAs and therefore contribute to regulatory network rewiring. Our analysis uncovers a widespread expansion of isomiR and mRNA interaction networks compared with those seen in canonical small RNA analysis; this expansion suggests global gene regulation network perturbations by alternative small RNA variants or isoforms. Taken together, the variations in isomiRs that occur during miRNA processing and maturation are likely to play a far more complex and plastic role in gene regulation than previously anticipated.

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