Kinetic Analysis of Target RNA Binding and Slicing by Human Argonaute 2 Protein

2016 ◽  
pp. 277-290
Author(s):  
Sarah Willkomm ◽  
Tobias Restle
Keyword(s):  
Kinetic Analysis ◽  
Rna Binding ◽  
Argonaute 2 ◽  
Target Rna

scholarly journals SCOPE enables type III CRISPR-Cas diagnostics using flexible targeting and stringent CARF ribonuclease activation

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jurre A. Steens ◽  
Yifan Zhu ◽  
David W. Taylor ◽  
Jack P. K. Bravo ◽  
Stijn H. P. Prinsen ◽  
...  
Keyword(s):  
Immune Response ◽  
Diagnostic Tool ◽  
Nasal Swab ◽  
Rna Binding ◽  
Seed Region ◽  
Base Pairing ◽  
Specific Detection ◽  
Type Iii ◽  
Single Host ◽  
Target Rna

AbstractCharacteristic properties of type III CRISPR-Cas systems include recognition of target RNA and the subsequent induction of a multifaceted immune response. This involves sequence-specific cleavage of the target RNA and production of cyclic oligoadenylate (cOA) molecules. Here we report that an exposed seed region at the 3′ end of the crRNA is essential for target RNA binding and cleavage, whereas cOA production requires base pairing at the 5′ end of the crRNA. Moreover, we uncover that the variation in the size and composition of type III complexes within a single host results in variable seed regions. This may prevent escape by invading genetic elements, while controlling cOA production tightly to prevent unnecessary damage to the host. Lastly, we use these findings to develop a new diagnostic tool, SCOPE, for the specific detection of SARS-CoV-2 from human nasal swab samples, revealing sensitivities in the atto-molar range.

scholarly journals Simultaneous silencing of two different Arabidopsis genes with a novel virus-induced gene silencing vector

Plant Methods ◽  
2021 ◽  
Vol 17 (1) ◽  
Author(s):  
Kunxin Wu ◽  
Yadan Wu ◽  
Chunwei Zhang ◽  
Yan Fu ◽  
Zhixin Liu ◽  
...  
Keyword(s):  
Gene Silencing ◽  
Double Mutant ◽  
Target Genes ◽  
Rna Binding ◽  
Protein Product ◽  
Antiviral Defense ◽  
Virus Induced Gene Silencing ◽  
Argonaute 2 ◽  
Plant Genes ◽  
Silencing Pathways

Abstract Background Virus-induced gene silencing (VIGS) is a useful tool for functional characterizations of plant genes. However, the penetrance of VIGS varies depending on the genes to be silenced, and has to be evaluated by examining the transcript levels of target genes. Results In this report, we report the development of a novel VIGS vector that permits a preliminary assessment of the silencing penetrance. This new vector is based on an attenuated variant of Turnip crinkle virus (TCV) known as CPB that can be readily used in Arabidopsis thaliana to interrogate genes of this model plant. A CPB derivative, designated CPB1B, was produced by inserting a 46 nucleotide section of the Arabidopsis PHYTOENE DESATURASE (PDS) gene into CPB, in antisense orientation. CPB1B induced robust PDS silencing, causing easily visible photobleaching in systemically infected Arabidopsis leaves. More importantly, CPB1B can accommodate additional inserts, derived from other Arabidopsis genes, causing the silencing of two or more genes simultaneously. With photobleaching as a visual marker, we adopted the CPB1B vector to validate the involvement of DICER-LIKE 4 (DCL4) in antiviral defense against TCV. We further revealed the involvement of ARGONAUTE 2 (AGO2) in PDS silencing and antiviral defense against TCV in dcl2drb4 double mutant plants. These results demonstrated that DOUBLE-STRANDED RNA-BINDING PROTEIN 4 (DRB4), whose protein product (DRB4) commonly partners with DCL4 in the antiviral silencing pathway, was dispensable for PDS silencing induced by CPB1B derivative in dcl2drb4 double mutant plants. Conclusions The CPB1B-based vector developed in this work is a valuable tool with visualizable indicator of the silencing penetrance for interrogating Arabidopsis genes, especially those involved in the RNA silencing pathways.

scholarly journals Specificity and sensitivity of an RNA targeting type III CRISPR complex coupled with a NucC endonuclease effector

2021 ◽  
Author(s):  
Sabine Gruschow ◽  
Catherine S Adamson ◽  
Malcolm F White
Keyword(s):  
Rna Binding ◽  
Limit Of Detection ◽  
Flanking Sequence ◽  
Guide Rna ◽  
Type Iii ◽  
Specificity And Sensitivity ◽  
Virus Rna ◽  
Messenger Molecules ◽  
Target Rna

Type III CRISPR systems detect invading RNA, resulting in the activation of the enzymatic Cas10 subunit. The Cas10 cyclase domain generates cyclic oligoadenylate (cOA) second messenger molecules, activating a variety of effector nucleases that degrade nucleic acids to provide immunity. The prophage-encoded Vibrio metoecus type III-B (VmeCmr) locus is uncharacterised, lacks the HD nuclease domain in Cas10 and encodes a NucC DNA nuclease effector that is also found associated with Cyclic-oligonucleotide-based anti-phage signalling systems (CBASS). Here we demonstrate that VmeCmr is activated by target RNA binding, generating cyclic-triadenylate (cA3) to stimulate a robust NucC-mediated DNase activity. The specificity of VmeCmr is probed, revealing the importance of specific nucleotide positions in segment 1 of the RNA duplex and the protospacer flanking sequence (PFS). We harness this programmable system to demonstrate the potential for a highly specific and sensitive assay for detection of the SARS-CoV-2 virus RNA with a limit of detection (LoD) of 2 fM using a commercial plate reader without any extrinsic amplification step. The sensitivity is highly dependent on the guide RNA used, suggesting that target RNA secondary structure plays an important role that may also be relevant in vivo.

scholarly journals Sorting Mechanisms for MicroRNAs into Extracellular Vesicles and Their Associated Diseases

Cells ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 1044 ◽  
Author(s):  
Michael Groot ◽  
Heedoo Lee
Keyword(s):  
Extracellular Vesicles ◽  
Potential Role ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Transport Proteins ◽  
Caveolin 1 ◽  
Argonaute 2 ◽  
Disease States ◽  
Mirna Content

Extracellular vesicles (EV) are secretory membranous elements used by cells to transport proteins, lipids, mRNAs, and microRNAs (miRNAs). While their existence has been known for many years, only recently has research begun to identify their function in intercellular communication and gene regulation. Importantly, cells have the ability to selectively sort miRNA into EVs for secretion to nearby or distant targets. These mechanisms broadly include RNA-binding proteins such as hnRNPA2B1 and Argonaute-2, but also membranous proteins involved in EV biogenesis such as Caveolin-1 and Neural Sphingomyelinase 2. Moreover, certain disease states have also identified dysregulated EV-miRNA content, shedding light on the potential role of selective sorting in pathogenesis. These pathologies include chronic lung disease, immune response, neuroinflammation, diabetes mellitus, cancer, and heart disease. In this review, we will overview the mechanisms whereby cells selectively sort miRNA into EVs and also outline disease states where EV-miRNAs become dysregulated.

scholarly journals High-Throughput Analysis Reveals Rules for Target RNA Binding and Cleavage by AGO2

2019 ◽  
Vol 75 (4) ◽  
pp. 741-755.e11 ◽  
Author(s):  
Winston R. Becker ◽  
Benjamin Ober-Reynolds ◽  
Karina Jouravleva ◽  
Samson M. Jolly ◽  
Phillip D. Zamore ◽  
...  
Keyword(s):  
High Throughput ◽  
Rna Binding ◽  
High Throughput Analysis ◽  
Throughput Analysis ◽  
Target Rna

scholarly journals Regulation of the RNA and DNA nuclease activities required for Pyrococcus furiosus Type III-B CRISPR–Cas immunity

2020 ◽  
Vol 48 (8) ◽  
pp. 4418-4434 ◽  
Author(s):  
Kawanda Foster ◽  
Sabine Grüschow ◽  
Scott Bailey ◽  
Malcolm F White ◽  
Michael P Terns
Keyword(s):  
Rna Binding ◽  
Pyrococcus Furiosus ◽  
Type Iii ◽  
Second Messenger Signaling ◽  
Biochemical Analyses ◽  
Rna Interaction ◽  
Dual Mechanism ◽  
Target Rna ◽  
Rna And Dna

Abstract Type III CRISPR–Cas prokaryotic immune systems provide anti-viral and anti-plasmid immunity via a dual mechanism of RNA and DNA destruction. Upon target RNA interaction, Type III crRNP effector complexes become activated to cleave both target RNA (via Cas7) and target DNA (via Cas10). Moreover, trans-acting endoribonucleases, Csx1 or Csm6, can promote the Type III immune response by destroying both invader and host RNAs. Here, we characterize how the RNase and DNase activities associated with Type III-B immunity in Pyrococcus furiosus (Pfu) are regulated by target RNA features and second messenger signaling events. In vivo mutational analyses reveal that either the DNase activity of Cas10 or the RNase activity of Csx1 can effectively direct successful anti-plasmid immunity. Biochemical analyses confirmed that the Cas10 Palm domains convert ATP into cyclic oligoadenylate (cOA) compounds that activate the ribonuclease activity of Pfu Csx1. Furthermore, we show that the HEPN domain of the adenosine-specific endoribonuclease, Pfu Csx1, degrades cOA signaling molecules to provide an auto-inhibitory off-switch of Csx1 activation. Activation of both the DNase and cOA generation activities require target RNA binding and recognition of distinct target RNA 3′ protospacer flanking sequences. Our results highlight the complex regulatory mechanisms controlling Type III CRISPR immunity.

scholarly journals TRIM25 Is Required for the Antiviral Activity of Zinc Finger Antiviral Protein

2017 ◽  
Vol 91 (9) ◽  
Author(s):  
Xiaojiao Zheng ◽  
Xinlu Wang ◽  
Fan Tu ◽  
Qin Wang ◽  
Zusen Fan ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Zinc Finger ◽  
Ebola Virus ◽  
Rna Binding ◽  
E3 Ligase ◽  
Antiviral Protein ◽  
Viral Mrnas ◽  
Target Mrna ◽  
Ubiquitin E3 Ligase ◽  
Target Rna

ABSTRACTZinc finger antiviral protein (ZAP) is a host factor that specifically inhibits the replication of certain viruses by binding to viral mRNAs and repressing the translation and/or promoting the degradation of target mRNA. In addition, ZAP regulates the expression of certain cellular genes. Here, we report that tripartite motif-containing protein 25 (TRIM25), a ubiquitin E3 ligase, is required for the antiviral activity of ZAP. Downregulation of endogenous TRIM25 abolished ZAP's antiviral activity. The E3 ligase activity of TRIM25 is required for this regulation. TRIM25 mediated ZAP ubiquitination, but the ubiquitination of ZAP itself did not seem to be required for its antiviral activity. Downregulation of endogenous ubiquitin or overexpression of the deubiquitinase OTUB1 impaired ZAP's activity. We provide evidence indicating that TRIM25 modulates the target RNA binding activity of ZAP. These results uncover a mechanism by which the antiviral activity of ZAP is regulated.IMPORTANCEZAP is a host antiviral factor that specifically inhibits the replication of certain viruses, including HIV-1, Sindbis virus, and Ebola virus. ZAP binds directly to target mRNA, and it represses the translation and promotes the degradation of target mRNA. While the mechanisms by which ZAP posttranscriptionally inhibits target RNA expression have been extensively studied, how its antiviral activity is regulated is not very clear. Here, we report that TRIM25, a ubiquitin E3 ligase, is required for the antiviral activity of ZAP. Downregulation of endogenous TRIM25 remarkably abolished ZAP's activity. TRIM25 is required for ZAP optimal binding to target mRNA. These results help us to better understand how the antiviral activity of ZAP is regulated.

scholarly journals Type III CRISPR-Cas systems generate cyclic oligoadenylate second messengers to activate Csm6 RNases

2017 ◽  
Author(s):  
Ole Niewoehner ◽  
Carmela Garcia-Doval ◽  
Jakob T. Rostøl ◽  
Christian Berk ◽  
Frank Schwede ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Rna Binding ◽  
Second Messengers ◽  
Allosteric Activation ◽  
Conceptual Similarity ◽  
Type Iii ◽  
Rna Transcripts ◽  
Rna Targeting ◽  
Target Rna

ABSTRACTIn many prokaryotes, type III CRISPR–Cas systems detect and degrade invasive genetic elements by an RNA-guided, RNA-targeting multisubunit interference complex that possesses dual RNase and DNase activities. The CRISPR-associated protein Csm6 additionally contributes to interference by functioning as a standalone ribonuclease that degrades invader RNA transcripts, but the mechanism linking invader sensing to Csm6 activity is not understood. Here we show that Csm6 proteins are activated through a second messenger generated by the type III interference complex. Upon target RNA binding by the type III interference complex, the Cas10 subunit converts ATP into a cyclic oligoadenylate product, which allosterically activates Csm6 by binding to its CARF domain. CARF domain mutations that abolish allosteric activation inhibit Csm6 activity in vivo, and mutations in the Cas10 Palm domain phenocopy loss of Csm6. Together, these results point to a hitherto unprecedented mechanism for regulation of CRISPR interference that bears striking conceptual similarity to oligoadenylate signalling in mammalian innate immunity.

scholarly journals Combinatorial recognition of clustered RNA elements by a multidomain RNA-binding protein, IMP3

2018 ◽  
Author(s):  
Tim Schneider ◽  
Lee-Hsueh Hung ◽  
Masood Aziz ◽  
Anna Wilmen ◽  
Stephanie Thaum ◽  
...  
Keyword(s):  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Binding Protein ◽  
Rna Binding Protein ◽  
Binding Domains ◽  
Systematic Strategy ◽  
Rna Elements ◽  
Target Rna

AbstractHow multidomain RNA-binding proteins recognize their specific target sequences, based on a combinatorial code, represents a fundamental unsolved question and has not been studied systematically so far. Here we focus on a prototypical multidomain RNA-binding protein, IMP3 (also called IGF2BP3), which contains six RNA-binding domains (RBDs): four KH and two RRM domains. We have established an integrative systematic strategy, combining single-domain-resolved SELEX-seq, motif-spacing analyses, in vivo iCLIP, functional validation assays, and structural biology. This approach identifies the RNA-binding specificity and RNP topology of IMP3, involving all six RBDs and a cluster of up to five distinct and appropriately spaced CA-rich and GGC-core RNA elements, covering a >100 nucleotide-long target RNA region. Our generally applicable approach explains both specificity and flexibility of IMP3-RNA recognition, providing a paradigm for the function of multivalent interactions with multidomain RNA-binding proteins in gene regulation.

Novel insights toward human stroke-related epigenetics: circular RNA and its impact in poststroke processes

Epigenomics ◽  
2020 ◽  
Vol 12 (22) ◽  
pp. 1957-1968
Author(s):  
Pablo W Silva ◽  
Samara M M Shimon ◽  
Leonardo M de Brito ◽  
Laís Reis-das-Mercês ◽  
Leandro Magalhães ◽  
...  
Keyword(s):  
Rna Binding ◽  
Rna Binding Proteins ◽  
Enrichment Analysis ◽  
Functional Enrichment Analysis ◽  
Circular Rna ◽  
Functional Enrichment ◽  
Circular Rnas ◽  
Global Expression Profile ◽  
Human Stroke ◽  
Target Rna

Aim: Circular RNAs (circRNAs) are dysregulated in complex diseases, so we investigated their global expression profile in stroke. Material & methods: Public RNA-Seq data of human ischemic stroke lesion tissues and controls were used to perform the global expression analysis. Target RNA binding proteins and microRNAs were predicted in silico. Functional enrichment analysis was performed to infer the circRNAs’ potential roles. Results: We found that circRNAs are potentially involved in synaptic components and transmission, inflammation and ataxia. An integrative analysis revealed that hsa_circ_0078299 and FXN may be major players in the molecular stroke-context. Conclusion: Our results suggest a broad involvement of circRNAs in some stroke-related processes, indicating their potential as therapeutic targets to allow neuroprotection and brain recovery.

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