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Gene Apr 2024Argonaute (Ago) proteins act as key elements in RNA interference (RNAi) pathway, orchestrating the intricate machinery of gene regulation within eukaryotic cells. Within... (Review)
Review
Argonaute (Ago) proteins act as key elements in RNA interference (RNAi) pathway, orchestrating the intricate machinery of gene regulation within eukaryotic cells. Within the RNAi pathway, small RNA molecules, including microRNA (miRNA), small interfering RNA (siRNA), and PIWI-interacting RNA (piRNA), collaborate with Ago family member proteins such as Ago1, Ago2, and Ago3 to form the RNA-induced silencing complex (RISC). This RISC complex, in turn, either cleaves the target mRNA or inhibits the process of protein translation. The precise contributions of Ago proteins have been well-established in numerous animals and plants, although they still remain unclear in some insect species. This review aims to shed light on the specific roles played by Ago proteins within the RNAi mechanism in a destructive lepidopteran pest, the diamondback moth (Plutella xylostella). Furthermore, we explore the potential of double-stranded RNA (dsRNA)-mediated RNAi as a robust genetic tool in pest management strategies. Through an in-depth examination of Ago proteins and dsRNA-mediated RNAi, this review seeks to contribute to our understanding of innovative approaches for controlling this pest and potentially other insect species of agricultural significance.
Topics: Animals; RNA Interference; Argonaute Proteins; RNA, Small Interfering; MicroRNAs; RNA, Double-Stranded
PubMed: 38295911
DOI: 10.1016/j.gene.2024.148195 -
RNA (New York, N.Y.) Aug 2023The potential for microRNAs (miRNAs) to regulate gene expression remains incompletely understood. DROSHA initiates the biogenesis of miRNAs while variants of Argonaute...
The potential for microRNAs (miRNAs) to regulate gene expression remains incompletely understood. DROSHA initiates the biogenesis of miRNAs while variants of Argonaute (AGO) and trinucleotide repeat containing six (TNRC6) family proteins form complexes with miRNAs to facilitate RNA recognition and gene regulation. Here we investigate the fate of miRNAs in the absence of these critical RNAi protein factors. Knockout of expression reduces levels of some miRNAs annotated in miRBase but not others. The identity of miRNAs with reduced expression matches the identity of miRNAs previously identified by experimental approaches. The MirGeneDB resource offers the closest alignment with experimental results. In contrast, the loss of TNRC6 proteins had much smaller effects on miRNA levels. Knocking out AGO proteins, which directly contact the mature miRNA, decreased expression of the miRNAs most strongly associated with AGO2 as determined from enhanced crosslinking immunoprecipitation (AGO2-eCLIP). Evaluation of miRNA binding to endogenously expressed AGO proteins revealed that miRNA:AGO association was similar for AGO1, AGO2, AGO3, and AGO4. Our data emphasize the need to evaluate annotated miRNAs based on approximate cellular abundance, DROSHA-dependence, and physical association with AGO when forming hypotheses related to their function.
Topics: MicroRNAs; RNA Interference; Argonaute Proteins; Gene Expression Regulation; Trinucleotide Repeats
PubMed: 37169394
DOI: 10.1261/rna.079647.123 -
Nature Communications Nov 2023Argonaute proteins (Agos) bind short nucleic acids as guides and are directed by them to recognize target complementary nucleic acids. Diverse prokaryotic Agos (pAgos)...
Argonaute proteins (Agos) bind short nucleic acids as guides and are directed by them to recognize target complementary nucleic acids. Diverse prokaryotic Agos (pAgos) play potential functions in microbial defense. The functions and mechanisms of a group of full-length yet catalytically inactive pAgos, long-B pAgos, remain unclear. Here, we show that most long-B pAgos are functionally connected with distinct associated proteins, including nucleases, Sir2-domain-containing proteins and trans-membrane proteins, respectively. The long-B pAgo-nuclease system (BPAN) is activated by guide RNA-directed target DNA recognition and performs collateral DNA degradation in vitro. In vivo, the system mediates genomic DNA degradation after sensing invading plasmid, which kills the infected cells and results in the depletion of the invader from the cell population. Together, the BPAN system provides immunoprotection via abortive infection. Our data also suggest that the defense strategy is employed by other long-B pAgos equipped with distinct associated proteins.
Topics: Argonaute Proteins; Prokaryotic Cells; DNA; Plasmids; Nucleic Acids
PubMed: 37914725
DOI: 10.1038/s41467-023-42793-3 -
PeerJ 2024Environmental stresses diversely affect multiple processes related to the growth, development, and yield of many crops worldwide. In response, plants have developed... (Review)
Review
Environmental stresses diversely affect multiple processes related to the growth, development, and yield of many crops worldwide. In response, plants have developed numerous sophisticated defense mechanisms at the cellular and subcellular levels to react and adapt to biotic and abiotic stressors. RNA silencing, which is an innate immune mechanism, mediates sequence-specific gene expression regulation in higher eukaryotes. ARGONAUTE (AGO) proteins are essential components of the RNA-induced silencing complex (RISC). They bind to small noncoding RNAs (sRNAs) and target complementary RNAs, causing translational repression or triggering endonucleolytic cleavage pathways. In this review, we aim to illustrate the recently published molecular functions, regulatory mechanisms, and biological roles of AGO family proteins in model plants and cash crops, especially in the defense against diverse biotic and abiotic stresses, which could be helpful in crop improvement and stress tolerance in various plants.
Topics: Plant Proteins; Argonaute Proteins; Gene Expression Regulation, Plant; RNA-Induced Silencing Complex; Crops, Agricultural
PubMed: 38560454
DOI: 10.7717/peerj.17115 -
Science China. Life Sciences Apr 2024PIWI-interacting RNAs (piRNAs) are a class of small noncoding RNA molecules that specifically bind to piwi protein family members to exert regulatory functions in germ... (Review)
Review
PIWI-interacting RNAs (piRNAs) are a class of small noncoding RNA molecules that specifically bind to piwi protein family members to exert regulatory functions in germ cells. Recent studies have found that piRNAs, as tissue-specific molecules, both play oncogenic and tumor suppressive roles in cancer progression, including cancer cell proliferation, metastasis, chemoresistance and stemness. Additionally, the atypical manifestation of piRNAs and PIWI proteins in various malignancies presents a promising strategy for the identification of novel biomarkers and therapeutic targets in the diagnosis and management of tumors. Nonetheless, the precise functions of piRNAs in cancer progression and their underlying mechanisms have yet to be fully comprehended. This review aims to examine current research on the biogenesis and functions of piRNA and its burgeoning importance in cancer progression, thereby offering novel perspectives on the potential utilization of piRNAs and piwi proteins in the management and treatment of advanced cancer.
Topics: Humans; Argonaute Proteins; Neoplasms; Piwi-Interacting RNA; RNA, Small Interfering; RNA, Small Untranslated
PubMed: 38198029
DOI: 10.1007/s11427-023-2491-7 -
Nucleic Acids Research Sep 2023Programmable site-specific nucleases promise to unlock myriad applications in basic biology research, biotechnology and gene therapy. Gene-editing systems have...
Programmable site-specific nucleases promise to unlock myriad applications in basic biology research, biotechnology and gene therapy. Gene-editing systems have revolutionized our ability to engineer genomes across diverse eukaryotic species. However, key challenges, including delivery, specificity and targeting organellar genomes, pose barriers to translational applications. Here, we use peptide nucleic acids (PNAs) to facilitate precise DNA strand invasion and unwinding, enabling prokaryotic Argonaute (pAgo) proteins to specifically bind displaced single-stranded DNA and introduce site-specific double-strand breaks (DSBs) independent of the target sequence. We named this technology PNA-assisted pAgo editing (PNP editing) and determined key parameters for designing PNP editors to efficiently generate programable site-specific DSBs. Our design allows the simultaneous use of multiple PNP editors to generate multiple site-specific DSBs, thereby informing design considerations for potential in vitro and in vivo applications, including genome editing.
Topics: CRISPR-Cas Systems; DNA; DNA Breaks, Double-Stranded; Gene Editing; Genome; Peptide Nucleic Acids; Argonaute Proteins
PubMed: 37560931
DOI: 10.1093/nar/gkad655 -
RNA (New York, N.Y.) Oct 2023RNA-directed transposon silencing operates in the mammalian soma and germline to safeguard genomic integrity. The piRNA pathway and the HUSH complex identify active...
RNA-directed transposon silencing operates in the mammalian soma and germline to safeguard genomic integrity. The piRNA pathway and the HUSH complex identify active transposons through recognition of their nascent transcripts, but mechanistic understanding of how these distinct pathways evolved is lacking. TASOR is an essential component of the HUSH complex. TASOR's DUF3715 domain adopts a pseudo-PARP structure and is required for transposon silencing in a manner independent of complex assembly. TEX15, an essential piRNA pathway factor, also contains the DUF3715 domain. Here, we show that TASOR's and TEX15's DUF3715 domain share extensive structural homology. We found that the DUF3715 domain arose in early eukaryotes and that in vertebrates it is restricted to TEX15, TASOR, and TASORB orthologs. While TASOR-like proteins are found throughout metazoa, TEX15 is vertebrate-specific. The branching of TEX15 and the TASOR-like DUF3715 domain likely occurred in early metazoan evolution. Remarkably, despite this vast evolutionary distance, the DUF3715 domain from divergent TEX15 sequences can functionally substitute the DUF3715 domain of TASOR and mediates transposon silencing. We have thus termed this domain of unknown function as the RNA-directed pseudo-PARP transposon silencing (RDTS) domain. In summary, we show an unexpected functional link between these critical transposon silencing pathways.
Topics: Animals; RNA, Small Interfering; Poly(ADP-ribose) Polymerase Inhibitors; RNA Interference; Genome; Argonaute Proteins; Piwi-Interacting RNA; Mammals; DNA Transposable Elements; Drosophila Proteins; Drosophila melanogaster
PubMed: 37433650
DOI: 10.1261/rna.079693.123 -
Viruses Mar 2024As a mosquito-borne flavivirus, Zika virus (ZIKV) has been identified as a global health threat. The virus has been linked to severe congenital disabilities, including...
As a mosquito-borne flavivirus, Zika virus (ZIKV) has been identified as a global health threat. The virus has been linked to severe congenital disabilities, including microcephaly and other congenital malformations, resulting in fatal intrauterine death. Therefore, developing sensitive and specific methods for the early detection and accurate diagnosis of the ZIKV is essential for controlling its spread and mitigating its impact on public health. Herein, we set up a novel nucleic acid detection system based on Argonaute (Ago)-mediated nucleic acid detection, targeting the non-structural protein 5 (NS5) region of the ZIKV genome (abbreviated ZIKV-PAND). Without preamplification with the polymerase chain reaction (PCR), the minimum detection concentration (MDC) of ZIKV-PAND was about 10 nM. When introducing an amplification step, the MDC can be dramatically decreased to the aM level (8.3 aM), which is comparable to qRT-PCR assay (1.6 aM). In addition, the diagnostic findings from the analysis of simulated clinical samples or Zika virus samples using ZIKV-PAND show a complete agreement of 100% with qRT-PCR assays. This correlation can aid in the implementation of molecular testing for clinical diagnoses and the investigation of ZIKV infection on an epidemiological scale.
Topics: Zika Virus; Zika Virus Infection; Humans; Viral Nonstructural Proteins; Pyrococcus furiosus; Argonaute Proteins; Sensitivity and Specificity; RNA, Viral; Molecular Diagnostic Techniques; Nucleic Acid Amplification Techniques; Genome, Viral
PubMed: 38675882
DOI: 10.3390/v16040539 -
Molecular Plant Pathology Aug 2023RNA silencing, a core part of plants' antiviral defence, requires the ARGONAUTE, DICER-like, and RNA-dependent RNA polymerase proteins. However, how these proteins...
RNA silencing, a core part of plants' antiviral defence, requires the ARGONAUTE, DICER-like, and RNA-dependent RNA polymerase proteins. However, how these proteins contribute to watermelon's RNA interference (RNAi) pathway response to cucumber green mottle mosaic virus (CGMMV) has not been characterized. Here, we identify seven ClAGO, four ClDCL, and 11 ClRDR genes in watermelon and analyse their expression profiles when infected with CGMMV. ClAGO1 and ClAGO5 expression levels were highly induced by CGMMV infection. The results of ClAGO1 and ClAGO5 overexpression and silencing experiments suggest that these genes play central roles in watermelon's antiviral defence. Furthermore, co-immunoprecipitation and bimolecular fluorescence complementation experiments showed that ClAGO1 interacts with ClAGO5 in vivo, suggesting that ClAGO1 and ClAGO5 co-regulate watermelon defence against CGMMV infection. We also identified the ethylene response factor (ERF) binding site in the promoters of the ClAGO1 and ClAGO5 genes, and ethylene (ETH) treatment significantly increased ClAGO5 expression. Two ERF genes (Cla97C08G147180 and Cla97C06G122830) closely related to ClAGO5 expression were identified using co-expression analysis. Subcellular localization revealed that two ERFs and ClAGO5 predominantly localize at the nucleus, suggesting that enhancement of resistance to CGMMV by ETH is probably achieved through ClAGO5 but not ClAGO1. Our findings reveal aspects of the mechanisms underlying RNA silencing in watermelon against CGMMV.
Topics: Citrullus; Tobamovirus; Promoter Regions, Genetic; Ethylenes; Plant Diseases
PubMed: 37118922
DOI: 10.1111/mpp.13344 -
Nucleic Acids Research Feb 2024MicroRNAs (miRNAs) guide Argonaute (AGO) proteins to bind mRNA targets. Although most targets are destabilized by miRNA-AGO binding, some targets induce degradation of... (Review)
Review
MicroRNAs (miRNAs) guide Argonaute (AGO) proteins to bind mRNA targets. Although most targets are destabilized by miRNA-AGO binding, some targets induce degradation of the miRNA instead. These special targets are also referred to as trigger RNAs. All triggers identified thus far have binding sites with greater complementarity to the miRNA than typical target sites. Target-directed miRNA degradation (TDMD) occurs when trigger RNAs bind the miRNA-AGO complex and recruit the ZSWIM8 E3 ubiquitin ligase, leading to AGO ubiquitination and proteolysis and subsequent miRNA destruction. More than 100 different miRNAs are regulated by ZSWIM8 in bilaterian animals, and hundreds of trigger RNAs have been predicted computationally. Disruption of individual trigger RNAs or ZSWIM8 has uncovered important developmental and physiologic roles for TDMD across a variety of model organisms and cell types. In this review, we highlight recent progress in understanding the mechanistic basis and functions of TDMD, describe common features of trigger RNAs, outline best practices for validating trigger RNAs, and discuss outstanding questions in the field.
Topics: Animals; Argonaute Proteins; Binding Sites; MicroRNAs; Proteolysis; Ubiquitination; RNA Stability
PubMed: 38224449
DOI: 10.1093/nar/gkae003