scholarly journals Dicer Functions in Aquatic Species

2011 ◽  
Vol 2011 ◽  
pp. 1-5 ◽  
Author(s):  
Yasuko Kitagishi ◽  
Naoko Okumura ◽  
Hitomi Yoshida ◽  
Chika Tateishi ◽  
Yuri Nishimura ◽  
...  
Keyword(s):  
Recent Progress ◽  
Defense Mechanism ◽  
Aquatic Species ◽  
Small Interfering Rnas ◽  
Rnase Iii ◽  
Catalytic Subunits ◽  
Double Stranded Rna ◽  
Related Research ◽  
Micro Rnas ◽  
Endogenous Genes

Dicer is an RNase III enzyme with two catalytic subunits, which catalyzes the cleavage of double-stranded RNA to small interfering RNAs and micro-RNAs, which are mainly involved in invasive nucleic acid defense and endogenous genes regulation. Dicer is abundantly expressed in embryos, indicating the importance of the protein in early embryonic development. In addition, Dicer is thought to be involved in defense mechanism against foreign nucleic acids such as viruses. This paper will mainly focus on the recent progress of Dicer-related research and discuss potential RNA interference pathways in aquatic species.

scholarly journals The Evolutionary Significance of RNAi in the Fungal Kingdom

2020 ◽  
Vol 21 (24) ◽  
pp. 9348
Author(s):  
Carlos Lax ◽  
Ghizlane Tahiri ◽  
José Alberto Patiño-Medina ◽  
José T. Cánovas-Márquez ◽  
José A. Pérez-Ruiz ◽  
...  
Keyword(s):  
Target Genes ◽  
Regulation Of Gene Expression ◽  
Genome Integrity ◽  
Evolutionary Significance ◽  
Messenger Rnas ◽  
Small Interfering Rnas ◽  
Rnase Iii ◽  
Double Stranded Rna ◽  
Main Component ◽  
Fungal Kingdom

RNA interference (RNAi) was discovered at the end of last millennium, changing the way scientists understood regulation of gene expression. Within the following two decades, a variety of different RNAi mechanisms were found in eukaryotes, reflecting the evolutive diversity that RNAi entails. The essential silencing mechanism consists of an RNase III enzyme called Dicer that cleaves double-stranded RNA (dsRNA) generating small interfering RNAs (siRNAs), a hallmark of RNAi. These siRNAs are loaded into the RNA-induced silencing complex (RISC) triggering the cleavage of complementary messenger RNAs by the Argonaute protein, the main component of the complex. Consequently, the expression of target genes is silenced. This mechanism has been thoroughly studied in fungi due to their proximity to the animal phylum and the conservation of the RNAi mechanism from lower to higher eukaryotes. However, the role and even the presence of RNAi differ across the fungal kingdom, as it has evolved adapting to the particularities and needs of each species. Fungi have exploited RNAi to regulate a variety of cell activities as different as defense against exogenous and potentially harmful DNA, genome integrity, development, drug tolerance, or virulence. This pathway has offered versatility to fungi through evolution, favoring the enormous diversity this kingdom comprises.

scholarly journals Antiviral Defense Involves AGO4 in an Arabidopsis–Potexvirus Interaction

2016 ◽  
Vol 29 (11) ◽  
pp. 878-888 ◽  
Author(s):  
Chantal Brosseau ◽  
Mohamed El Oirdi ◽  
Ayooluwa Adurogbangba ◽  
Xiaofang Ma ◽  
Peter Moffett
Keyword(s):  
Gene Expression ◽  
Nuclear Localization ◽  
Rna Silencing ◽  
Defense Mechanism ◽  
Rna Viruses ◽  
Antiviral Defense ◽  
Double Stranded Rna ◽  
Micro Rnas ◽  
Plantago Asiatica ◽  
Antiviral Activities

In plants, RNA silencing regulates gene expression through the action of Dicer-like (DCL) and Argonaute (AGO) proteins via micro RNAs and RNA-dependent DNA methylation (RdDM). In addition, RNA silencing functions as an antiviral defense mechanism by targeting virus-derived double-stranded RNA. Plants encode multiple AGO proteins with specialized functions, including AGO4-like proteins that affect RdDM and AGO2, AGO5, and AGO1, which have antiviral activities. Here, we show that AGO4 is also required for defense against the potexvirus Plantago asiatica mosaic virus (PlAMV), most likely independent of RdDM components such as DCL3, Pol IV, and Pol V. Transient assays showed that AGO4 has direct antiviral activity on PlAMV and, unlike RdDM, this activity does not require nuclear localization of AGO4. Furthermore, although PlAMV infection causes a decrease in AGO4 expression, PlAMV causes a change in AGO4 localization from a largely nuclear to a largely cytoplasmic distribution. These results indicate an important role for AGO4 in targeting plant RNA viruses as well as demonstrating novel mechanisms of regulation of and by AGO4, independent of its canonical role in regulating gene expression by RdDM.

scholarly journals RNA Interference: Biology, Mechanism, and Applications

2003 ◽  
Vol 67 (4) ◽  
pp. 657-685 ◽  
Author(s):  
Neema Agrawal ◽  
P. V. N. Dasaradhi ◽  
Asif Mohmmed ◽  
Pawan Malhotra ◽  
Raj K. Bhatnagar ◽  
...  
Keyword(s):  
Gene Silencing ◽  
Defense Mechanisms ◽  
Specific Gene ◽  
Small Interfering Rnas ◽  
Allelic Series ◽  
Rnase Iii ◽  
Heterochromatin Formation ◽  
Regulatory Processes ◽  
Micro Rnas ◽  
And Function

SUMMARY Double-stranded RNA-mediated interference (RNAi) is a simple and rapid method of silencing gene expression in a range of organisms. The silencing of a gene is a consequence of degradation of RNA into short RNAs that activate ribonucleases to target homologous mRNA. The resulting phenotypes either are identical to those of genetic null mutants or resemble an allelic series of mutants. Specific gene silencing has been shown to be related to two ancient processes, cosuppression in plants and quelling in fungi, and has also been associated with regulatory processes such as transposon silencing, antiviral defense mechanisms, gene regulation, and chromosomal modification. Extensive genetic and biochemical analysis revealed a two-step mechanism of RNAi-induced gene silencing. The first step involves degradation of dsRNA into small interfering RNAs (siRNAs), 21 to 25 nucleotides long, by an RNase III-like activity. In the second step, the siRNAs join an RNase complex, RISC (RNA-induced silencing complex), which acts on the cognate mRNA and degrades it. Several key components such as Dicer, RNA-dependent RNA polymerase, helicases, and dsRNA endonucleases have been identified in different organisms for their roles in RNAi. Some of these components also control the development of many organisms by processing many noncoding RNAs, called micro-RNAs. The biogenesis and function of micro-RNAs resemble RNAi activities to a large extent. Recent studies indicate that in the context of RNAi, the genome also undergoes alterations in the form of DNA methylation, heterochromatin formation, and programmed DNA elimination. As a result of these changes, the silencing effect of gene functions is exercised as tightly as possible. Because of its exquisite specificity and efficiency, RNAi is being considered as an important tool not only for functional genomics, but also for gene-specific therapeutic activities that target the mRNAs of disease-related genes.

scholarly journals Contribution of Small RNA Pathway to Interactions of Rice with Pathogens and Insect Pests

Rice ◽  
2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Qin Feng ◽  
Yan Li ◽  
Zhi-Xue Zhao ◽  
Wen-Ming Wang
Keyword(s):  
Small Rna ◽  
Small Rnas ◽  
Recent Progress ◽  
Target Genes ◽  
Insect Pests ◽  
Circular Rnas ◽  
Small Interfering Rnas ◽  
Double Stranded Rna ◽  
Argonaute Proteins ◽  
Non Coding Rnas

AbstractSmall RNAs (sRNAs) are mainly classified into microRNAs (miRNAs) and small interfering RNAs (siRNAs) according to their origin. miRNAs originate from single-stranded RNA precursors, whereas siRNAs originate from double-stranded RNA precursors that are synthesized by RNA-dependent RNA polymerases. Both of single-stranded and double-stranded RNA precursors are processed into sRNAs by Dicer-like proteins. Then, the sRNAs are loaded into ARGONAUTE proteins, forming RNA-induced silencing complexes (RISCs). The RISCs repress the expression of target genes with sequences complementary to the sRNAs through the cleavage of transcripts, the inhibition of translation or DNA methylation. Here, we summarize the recent progress of sRNA pathway in the interactions of rice with various parasitic organisms, including fungi, viruses, bacteria, as well as insects. Besides, we also discuss the hormone signal in sRNA pathway, and the emerging roles of circular RNAs and long non-coding RNAs in rice immunity. Obviously, small RNA pathway may act as a part of rice innate immunity to coordinate with growth and development.

Current RNA-based Therapeutics in Clinical Trials

2019 ◽  
Vol 19 (3) ◽  
pp. 172-196 ◽  
Author(s):  
Ling-Yan Zhou ◽  
Zhou Qin ◽  
Yang-Hui Zhu ◽  
Zhi-Yao He ◽  
Ting Xu
Keyword(s):  
Clinical Trials ◽  
Rapid Development ◽  
Genetic Diseases ◽  
Three Dimensional ◽  
Therapeutic Effects ◽  
Messenger Rnas ◽  
Small Interfering Rnas ◽  
Rna Modifications ◽  
Guide Rna ◽  
Endogenous Genes

Long-term research on various types of RNAs has led to further understanding of diverse mechanisms, which eventually resulted in the rapid development of RNA-based therapeutics as powerful tools in clinical disease treatment. Some of the developing RNA drugs obey the antisense mechanisms including antisense oligonucleotides, small interfering RNAs, microRNAs, small activating RNAs, and ribozymes. These types of RNAs could be utilized to inhibit/activate gene expression or change splicing to provide functional proteins. In the meantime, some others based on different mechanisms like modified messenger RNAs could replace the dysfunctional endogenous genes to manage some genetic diseases, and aptamers with special three-dimensional structures could bind to specific targets in a high-affinity manner. In addition, the recent most popular CRISPR-Cas technology, consisting of a crucial single guide RNA, could edit DNA directly to generate therapeutic effects. The desired results from recent clinical trials indicated the great potential of RNA-based drugs in the treatment of various diseases, but further studies on improving delivery materials and RNA modifications are required for the novel RNA-based drugs to translate to the clinic. This review focused on the advances and clinical studies of current RNA-based therapeutics, analyzed their challenges and prospects.

scholarly journals Epigenetic memory effects in forest trees: a victory of “Michurinian biology”?

2017 ◽  
Vol 63 (4) ◽  
pp. 173-179 ◽  
Author(s):  
Dušan Gömöry ◽  
Matúš Hrivnák ◽  
Diana Krajmerová ◽  
Roman Longauer
Keyword(s):  
Molecular Mechanisms ◽  
Cytosine Methylation ◽  
Epigenetic Inheritance ◽  
Memory Effects ◽  
Forest Trees ◽  
Small Interfering Rnas ◽  
Adaptation To Climate Change ◽  
Growth Environment ◽  
Micro Rnas ◽  
Covalent Modifications

AbstractThe study reviews trait inheritance, which is in contradiction with the rules of Mendelian genetics, and which was object of controversies among biologists (sometimes with grave political consequences) in the USSR and Sovietcontrolled countries in the 1930s-1960s. “Carryover” or “memory” effects of the climate, to which maternal trees are exposed during seed development, on phenological behavior and other adaptively relevant traits of their offspring in conifers are mentioned; similar effects are associated with the germination and early growth environment. Molecular mechanisms underlying these effects include covalent modifications of DNA or DNA-associated proteins (cytosine methylation, various types of histone modifications), micro-RNAs and small interfering RNAs. Tools for the identification of these modifications are reviewed with a focus on cytosine methylation, along with an overview of the hitherto knowledge on the occurrence of DNA modifications in forest trees. The practical implications of epigenetic inheritance in forest trees are discussed with the focus on the adaptation to climate change and legislation on forest reproductive materials.

scholarly journals Micro RNAs: an arguable appraisal in medicine

2016 ◽  
Vol 50 (2) ◽  
pp. 106-124 ◽  
Author(s):  
K. Voglova ◽  
J. Bezakova ◽  
Iveta Herichova
Keyword(s):  
Clinical Trials ◽  
Human Body ◽  
Physiological State ◽  
Intercellular Signaling ◽  
Circulating Mirnas ◽  
Intracellular Space ◽  
Double Stranded Rna ◽  
Micro Rnas ◽  
Neural Diseases

AbstractMicro RNAs (miRNAs) represent a newly discovered class of regulatory molecules in the human body. miRNA is a short double stranded RNA sequence interfering with mRNA, causing in most cases, inhibition of translation. Synthesis of miRNAs shows an increasing developmental pattern and postnatally miRNAs are synthesized in all cells possessing transcriptional machinery. miRNAs usually target several mRNAs and therefore conclusive evidences proving their functions are not always ease to be acquired. In spite of this difficulty, functions of miRNAs were firmly established in the development, the cardiovascular and neural diseases, and cancer. Many miRNAs have been reported to be associated with physiological state of cells and/or tissues. This finding becomes fundamental, especially when consider that these miRNAs can be released from cell into intracellular space or circulation. Correlation between miRNA production in tissues and its contribution to multisource miRNA pool in the circulation is in a focus of biomarker-oriented researchers. Recently, circulating miRNAs have been suggested to be applicable as biomarkers in several types of cancer, cardiovascular injury, and diabetes. Role of miRNAs in the organism intercellular signaling is still under the broad investigation. Several miRNA mimics, intended for treatment of disease, are being currently tested in the clinical trials.

scholarly journals Unknown Areas of Activity of Human Ribonuclease Dicer: A Putative Deoxyribonuclease Activity

Molecules ◽  
2020 ◽  
Vol 25 (6) ◽  
pp. 1414 ◽  
Author(s):  
Marta Wojnicka ◽  
Agnieszka Szczepanska ◽  
Anna Kurzynska-Kokorniak
Keyword(s):  
Dnase Activity ◽  
Helicase Domain ◽  
Small Interfering Rnas ◽  
Rnase Iii ◽  
Domain Specific ◽  
Dsrna Binding ◽  
Small Regulatory Rnas ◽  
Paz Domain ◽  
Canonical Products ◽  
Truncated Variants

The Dicer ribonuclease plays a crucial role in the biogenesis of small regulatory RNAs (srRNAs) by processing long double-stranded RNAs and single-stranded hairpin RNA precursors into small interfering RNAs (siRNAs) and microRNAs (miRNAs), respectively. Dicer-generated srRNAs can control gene expression by targeting complementary transcripts and repressing their translation or inducing their cleavage. Human Dicer (hDicer) is a multidomain enzyme comprising a putative helicase domain, a DUF283 domain, platform, a PAZ domain, a connector helix, two RNase III domains (RNase IIIa and RNase IIIb) and a dsRNA-binding domain. Specific, ~20-base pair siRNA or miRNA duplexes with 2 nucleotide (nt) 3’-overhangs are generated by Dicer when an RNA substrate is anchored within the platform-PAZ-connector helix (PPC) region. However, increasing number of reports indicate that in the absence of the PAZ domain, binding of RNA substrates can occur by other Dicer domains. Interestingly, truncated variants of Dicer, lacking the PPC region, have been found to display a DNase activity. Inspired by these findings, we investigated how the lack of the PAZ domain, or the entire PPC region, would influence the cleavage activity of hDicer. Using immunopurified 3xFlag-hDicer produced in human cells and its two variants: one lacking the PAZ domain, and the other lacking the entire PPC region, we show that the PAZ domain deletion variants of hDicer are not able to process a pre-miRNA substrate, a dsRNA with 2-nt 3ʹ-overhangs, and a blunt-ended dsRNA. However, the PAZ deletion variants exhibit both RNase and DNase activity on short single-stranded RNA and DNAs, respectively. Collectively, our results indicate that when the PAZ domain is absent, other hDicer domains may contribute to substrate binding and in this case, non-canonical products can be generated.

Recent Progress in Relaxin-3-Related Research

2005 ◽  
Vol 1041 (1) ◽  
pp. 47-60 ◽  
Author(s):  
CHANGLU LIU ◽  
PASCAL BONAVENTURE ◽  
STEVEN W. SUTTON ◽  
JINGCAI CHEN ◽  
CHESTER KUEI ◽  
...  
Keyword(s):  
Recent Progress ◽  
Related Research
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