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Mikrochimica Acta Jul 2024A Pyrococcus furiosus Argonaute (PfAgo)-based biosensor is presented for alkaline phosphatase (ALP) activity detection in which the ALP-catalyzed hydrolysis of...
A Pyrococcus furiosus Argonaute (PfAgo)-based biosensor is presented for alkaline phosphatase (ALP) activity detection in which the ALP-catalyzed hydrolysis of 3'-phosphate-modified functional DNA activates the strand displacement amplification, and the amplicon mediates the fluorescent reporter cleavage as a guide sequence of PfAgo. Under the dual amplification mode of PfAgo-catalyzed multiple-turnover cleavage activity and pre-amplification technology, the developed method was successfully applied to ALP activity determination with a detection limit (LOD) of 0.0013 U L (3σ) and a detection range of 0.0025 to 1 U L within 90 min. The PfAgo-based method exhibits satisfactory analytic performance in the presence of potential interferents and in complex human serum samples. The proposed method shows several advantages, such as rapid analysis, high sensitivity, low-cost, and easy operation, and has great potential in disease evolution fundamental studies and clinical diagnosis applications.
Topics: Biosensing Techniques; Alkaline Phosphatase; Humans; Limit of Detection; Pyrococcus furiosus; Argonaute Proteins; Nucleic Acid Amplification Techniques; Enzyme Assays
PubMed: 38954110
DOI: 10.1007/s00604-024-06516-9 -
Nature Communications Jun 2024Argonaute proteins are the central effectors of RNA-guided RNA silencing pathways in eukaryotes, playing crucial roles in gene repression and defense against viruses and...
Argonaute proteins are the central effectors of RNA-guided RNA silencing pathways in eukaryotes, playing crucial roles in gene repression and defense against viruses and transposons. Eukaryotic Argonautes are subdivided into two clades: AGOs generally facilitate miRNA- or siRNA-mediated silencing, while PIWIs generally facilitate piRNA-mediated silencing. It is currently unclear when and how Argonaute-based RNA silencing mechanisms arose and diverged during the emergence and early evolution of eukaryotes. Here, we show that in Asgard archaea, the closest prokaryotic relatives of eukaryotes, an evolutionary expansion of Argonaute proteins took place. In particular, a deep-branching PIWI protein (HrAgo1) encoded by the genome of the Lokiarchaeon 'Candidatus Harpocratesius repetitus' shares a common origin with eukaryotic PIWI proteins. Contrasting known prokaryotic Argonautes that use single-stranded DNA as guides and/or targets, HrAgo1 mediates RNA-guided RNA cleavage, and facilitates gene silencing when expressed in human cells and supplied with miRNA precursors. A cryo-EM structure of HrAgo1, combined with quantitative single-molecule experiments, reveals that the protein displays structural features and target-binding modes that are a mix of those of eukaryotic AGO and PIWI proteins. Thus, this deep-branching archaeal PIWI may have retained an ancestral molecular architecture that preceded the functional and mechanistic divergence of eukaryotic AGOs and PIWIs.
Topics: Argonaute Proteins; Humans; RNA Interference; Archaea; RNA, Small Interfering; Archaeal Proteins; Cryoelectron Microscopy; MicroRNAs; Evolution, Molecular; Phylogeny
PubMed: 38951509
DOI: 10.1038/s41467-024-49452-1 -
Cell Communication and Signaling : CCS Jun 2024PIWI-interacting RNA (piRNA) is the most abundant small non-coding RNA in animal cells, typically 26-31 nucleotides in length and it binds with PIWI proteins, a... (Review)
Review
PIWI-interacting RNA (piRNA) is the most abundant small non-coding RNA in animal cells, typically 26-31 nucleotides in length and it binds with PIWI proteins, a subfamily of Argonaute proteins. Initially discovered in germ cells, piRNA is well known for its role in silencing transposons and maintaining genome integrity. However, piRNA is also present in somatic cells as well as in extracellular vesicles and exosomes. While piRNA has been extensively studied in various diseases, particular cancer, its function in immune diseases remains unclear. In this review, we summarize current research on piRNA in immune diseases. We first introduce the basic characteristics, biogenesis and functions of piRNA. Then, we review the association of piRNA with different types of immune diseases, including autoimmune diseases, immunodeficiency diseases, infectious diseases, and other immune-related diseases. piRNA is considered a promising biomarker for diseases, highlighting the need for further research into its potential mechanisms in disease pathogenesis.
Topics: Humans; RNA, Small Interfering; Animals; Immune System Diseases; Piwi-Interacting RNA
PubMed: 38943141
DOI: 10.1186/s12964-024-01724-5 -
Cellular and Molecular Life Sciences :... Jun 2024Cetuximab resistance has been a major challenge for head and neck squamous cell carcinoma (HNSCC) patients receiving targeted therapy. However, the mechanism that causes...
Cetuximab resistance has been a major challenge for head and neck squamous cell carcinoma (HNSCC) patients receiving targeted therapy. However, the mechanism that causes cetuximab resistance, especially microRNA (miRNA) regulation, remains unclear. Growing evidence suggests that miRNAs may act as "nuclear activating miRNAs" for targeting promoter regions or enhancers related to target genes. This study elucidates a novel mechanism underlying cetuximab resistance in HNSCC involving the nuclear activation of KDM7A transcription via miR-451a. Herein, small RNA sequencing, quantitative real-time polymerase chain reaction (qRT‒PCR) and fluorescence in situ hybridization (FISH) results provided compelling evidence of miR-451a nuclear enrichment in response to cetuximab treatment. Chromatin isolation via RNA purification, microarray analysis, and bioinformatic analysis revealed that miR-451a interacts with an enhancer region in KDM7A, activating its expression and further facilitating cetuximab resistance. It has also been demonstrated that the activation of KDM7A by nuclear miR-451a is induced by cetuximab treatment and is AGO2 dependent. Logistic regression analyses of 87 HNSCC samples indicated the significance of miR-451a and KDM7A in the development of cetuximab resistance. These discoveries support the potential of miR-451a and KDM7A as valuable biomarkers for cetuximab resistance and emphasize the function of nuclear-activating miRNAs.
Topics: Humans; MicroRNAs; Cetuximab; Drug Resistance, Neoplasm; Squamous Cell Carcinoma of Head and Neck; Head and Neck Neoplasms; Cell Line, Tumor; Gene Expression Regulation, Neoplastic; Jumonji Domain-Containing Histone Demethylases; Argonaute Proteins; Animals; Mice; Cell Nucleus; Female; Mice, Nude
PubMed: 38943031
DOI: 10.1007/s00018-024-05324-x -
Genes May 2024PIWI-interacting RNAs (piRNAs), a class of small non-coding RNAs (sncRNAs) with 24-32 nucleotides (nt), were initially identified in the reproductive system. Unlike... (Review)
Review
PIWI-interacting RNAs (piRNAs), a class of small non-coding RNAs (sncRNAs) with 24-32 nucleotides (nt), were initially identified in the reproductive system. Unlike microRNAs (miRNAs) or small interfering RNAs (siRNAs), piRNAs normally guide P-element-induced wimpy testis protein (PIWI) families to slice extensively complementary transposon transcripts without the seed pairing. Numerous studies have shown that piRNAs are abundantly expressed in the brain, and many of them are aberrantly regulated in central neural system (CNS) disorders. However, the role of piRNAs in the related developmental and pathological processes is unclear. The elucidation of piRNAs/PIWI would greatly improve the understanding of CNS development and ultimately lead to novel strategies to treat neural diseases. In this review, we summarized the relevant structure, properties, and databases of piRNAs and their functional roles in neural development and degenerative disorders. We hope that future studies of these piRNAs will facilitate the development of RNA-based therapeutics for CNS disorders.
Topics: Humans; RNA, Small Interfering; Animals; Argonaute Proteins; Nervous System Diseases; Neurogenesis
PubMed: 38927589
DOI: 10.3390/genes15060653 -
Antibiotics (Basel, Switzerland) Jun 2024Leptospirosis is a major zoonotic disease caused by pathogenic spirochetes in the genus Leptospira, affecting over a million people annually and causing approximately...
Leptospirosis is a major zoonotic disease caused by pathogenic spirochetes in the genus Leptospira, affecting over a million people annually and causing approximately 60,000 deaths. , a key causative agent, likely possesses defense systems against bacteriophages (leptophages), yet these systems are not well understood. We analyzed 402 genomes of using the DefenseFinder tool to identify and characterize the antiphage defense systems. We detected 24 unique systems, with CRISPR-Cas (Clustered Regularly Interspaced Short Palindromic Repeats and CRISPR-associated proteins), PrrC, Borvo, and Restriction-Modification (R-M) being the most prevalent. Notably, Cas were identified in all strains, indicating their central role in phage defense. Furthermore, there were variations in the antiphage system distribution across different serovars, suggesting unique evolutionary adaptations. For instance, Retron was found exclusively in the Canicola serovar, while prokaryotic Argonaute proteins (pAgo) were only detected in the Grippotyphosa serovar. These findings significantly enhance our understanding of 's antiphage defense mechanisms. They reveal the potential for the development of serovar-specific phage-based therapies and underscore the importance of further exploring these defense systems.
PubMed: 38927188
DOI: 10.3390/antibiotics13060522 -
Cell Reports Jun 2024Inhibition of nucleic acid targets is mediated by Argonaute (Ago) proteins guided by RNA or DNA. Although the mechanisms underpinning the functions of eukaryotic and...
Inhibition of nucleic acid targets is mediated by Argonaute (Ago) proteins guided by RNA or DNA. Although the mechanisms underpinning the functions of eukaryotic and "long" prokaryotic Ago proteins (pAgos) are well understood, those for short pAgos remain enigmatic. Here, we determine two cryoelectron microscopy structures of short pAgos in association with the NADase-domain-containing protein Sir2-APAZ from Geobacter sulfurreducens (GsSir2/Ago): the guide RNA-target DNA-loaded GsSir2/Ago quaternary complex (2.58 Å) and the dimer of the quaternary complex (2.93Å). These structures show that the nucleic acid binding causes profound conformational changes that result in disorder or partial dissociation of the Sir2 domain, suggesting that it adopts a NADase-active conformation. Subsequently, two RNA-/DNA-loaded GsSir2/Ago complexes form a dimer through their MID domains, further enhancing NADase activity through synergistic effects. The findings provide a structural basis for short-pAgo-mediated defense against invading nucleic acids.
PubMed: 38923459
DOI: 10.1016/j.celrep.2024.114391 -
Current Protocols Jun 2024The middle (MID) domain of eukaryotic Argonaute (Ago) proteins and archaeal and bacterial homologues mediates the interaction with the 5'-terminal nucleotide of miRNA...
The middle (MID) domain of eukaryotic Argonaute (Ago) proteins and archaeal and bacterial homologues mediates the interaction with the 5'-terminal nucleotide of miRNA and siRNA guide strands. The MID domain of human Ago2 (hAgo2) is comprised of 139 amino acids with a molecular weight of 15.56 kDa. MID adopts a Rossman-like beta1-alpha1-beta2-alpha2-beta3-alpha3-beta4-alpha4 fold with a nucleotide specificity loop between beta3 and alpha3. Multiple crystal structures of nucleotides bound to hAgo2 MID have been reported, whereby complexes were obtained by soaking ligands into crystals of MID domain alone. This protocol describes a simplified one-step approach to grow well-diffracting crystals of hAgo2 MID-nucleotide complexes by mixing purified His-SUMO-MID fusion protein, Ulp1 protease, and excess nucleotide in the presence of buffer and precipitant. The crystal structures of MID complexes with UMP, UTP and 2'-3' linked α-L-threofuranosyl thymidine-3'-triphosphate (tTTP) are presented. This article also describes fluorescence-based assays to measure dissociation constants (K) of MID-nucleotide interactions for nucleoside 5'-monophosphates and nucleoside 3',5'-bisphosphates. © 2024 The Authors. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Crystallization of Ago2 MID-nucleotide complexes Basic Protocol 2: Measurement of dissociation constant K between Ago2 MID and nucleotides.
Topics: Humans; Argonaute Proteins; Crystallography, X-Ray; Nucleotides; Protein Binding; Histidine; Crystallization; Protein Domains; Oligopeptides
PubMed: 38923271
DOI: 10.1002/cpz1.1088 -
Asian Pacific Journal of Cancer... Jun 2024The aim of this study was to evaluate the expression profiles of PIWI-like protein- 2 (PIWIL2), and HepPar1 and their immunohistochemical (IHC) characteristics in...
OBJECTIVE
The aim of this study was to evaluate the expression profiles of PIWI-like protein- 2 (PIWIL2), and HepPar1 and their immunohistochemical (IHC) characteristics in Hepatocellular Carcinoma (HCC), and determine their correlation with clinicopathological parameters of this type of cancer to determine their diagnostic value in combination.
METHODS
Seventy-five patients with HCC were assessed for the expression of PIWIL2 in serum and tissue using real-time polymerase chain reaction (RT-PCR) and IHC was performed for PIWIL2 and HepPar1 was performed on all patients.
RESULTS
A statistically significantly higher level of PIWIL2 was found in HCC compared to controls (p≤0.001). Both HepPar1 and PIWIL2 were detected in 84% of HCC cases, the diagnostic and prognostic factors for PIWIL2 were found to be significant in liver tumour tissue samples and non-tumorous sections p<0.001, and the same was observed for serum samples and results of healthy serum controls (p<0.001) when compared to AFP.
CONCLUSION
Our results affirm the hypothesis that reactivation of PIWI expression in various caner types is crucial for cancer development, and that a possible panel maybe used for these markers HCC diagnosis.
Topics: Humans; Carcinoma, Hepatocellular; Liver Neoplasms; Argonaute Proteins; Biomarkers, Tumor; Male; Female; Middle Aged; Prognosis; Case-Control Studies; Follow-Up Studies; Adult; alpha-Fetoproteins; Aged
PubMed: 38918675
DOI: 10.31557/APJCP.2024.25.6.2123 -
Frontiers in Bioengineering and... 2024Boolean gates, the fundamental components of digital circuits, have been widely investigated in synthetic biology because they permit the fabrication of biosensors and...
Boolean gates, the fundamental components of digital circuits, have been widely investigated in synthetic biology because they permit the fabrication of biosensors and facilitate biocomputing. This study was conducted to design and construct Boolean gates in the yeast , the main component of which was the RNA interference pathway (RNAi) that is naturally absent from the budding yeast cells. We tested different expression cassettes for the siRNA precursor (a giant hairpin sequence, a DNA fragment-flanked by one or two introns-between convergent promoters or transcribed separately in the sense and antisense directions) and placed different components under the control of the circuit inputs (i.e., the siRNA precursor or proteins such as the Dicer and the Argonaute). We found that RNAi-based logic gates are highly sensitive to promoter leakage and, for this reason, challenging to implement . Convergent-promoter architecture turned out to be the most reliable solution, even though the overall best performance was achieved with the most difficult design based on the siRNA precursor as a giant hairpin.
PubMed: 38895554
DOI: 10.3389/fbioe.2024.1392967