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1.
Methods Mol Biol ; 2788: 157-169, 2024.
Artículo en Inglés | MEDLINE | ID: mdl-38656513

RESUMEN

This chapter presents a comprehensive approach to predict novel miRNAs encoded by plant viruses and identify their target plant genes, through integration of various ab initio computational approaches. The predictive process begins with the analysis of plant viral sequences using the VMir Analyzer software. VMir Viewer software is then used to extract primary hairpins from these sequences. To distinguish real miRNA precursors from pseudo miRNA precursors, MiPred web-based software is employed. Verified real pre-miRNA sequences with a minimum free energy of < -20 Kcal/mol, are further analyzed using the RNAshapes software. Validation of predictions involves comparing them with available Expressed Sequence Tags (ESTs) from the relevant plant using BlastN. Short sequences with lengths ranging from 19 to 25 nucleotides and exhibiting <5 mismatches are prioritized for miRNA prediction. The precise locations of these short sequences within pre-miRNA structures generated using RNAshapes are meticulously identified, with a focus on those situated on the 5' and 3' arms of the structures, indicating potential miRNAs. Sequences within the arms of pre-miRNA structures are used to predict target sites within the ESTs of the specific plant, facilitated by psRNA Target software, revealing genes with potential regulatory roles in the plant. To confirm the outcome of target prediction, results are individually submitted to the RNAhybrid web-based software. For practical demonstration, this approach is applied to analyze African cassava mosaic virus (ACMV) and East African cassava mosaic virus-Uganda (EACMV-UG) viruses, as well as the ESTs of Jatropha and cassava.


Asunto(s)
Biología Computacional , MicroARNs , Virus de Plantas , ARN Viral , Programas Informáticos , MicroARNs/genética , Virus de Plantas/genética , Biología Computacional/métodos , ARN Viral/genética , Genes de Plantas , Conformación de Ácido Nucleico , Plantas/virología , Plantas/genética , Etiquetas de Secuencia Expresada
2.
Genes Dis ; 11(1): 382-396, 2024 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-37588203

RESUMEN

As the most common internal modification of mRNA, N6-methyladenosine (m6A) and its regulators modulate gene expression and play critical roles in various biological and pathological processes including tumorigenesis. It was reported previously that m6A methyltransferase (writer), methyltransferase-like 3 (METTL3) adds m6A in primary microRNAs (pri-miRNAs) and facilitates its processing into precursor miRNAs (pre-miRNAs). However, it is unknown whether m6A modification also plays a role in the maturation process of pre-miRNAs and (if so) whether such a function contributes to tumorigenesis. Here, we found that YTHDF2 is aberrantly overexpressed in acute myeloid leukemia (AML) patients, especially in relapsed patients, and plays an oncogenic role in AML. Moreover, YTHDF2 promotes expression of miR-126-3p (also known as miR-126, as it is the main product of precursor miR-126 (pre-miR-126)), a miRNA that was reported as an oncomiRNA in AML, through facilitating the processing of pre-miR-126 into mature miR-126. Mechanistically, YTHDF2 recognizes m6A modification in pre-miR-126 and recruits AGO2, a regulator of pre-miRNA processing, to promote the maturation of pre-miR-126. YTHDF2 positively and negatively correlates with miR-126 and miR-126's downstream target genes, respectively, in AML patients, and forced expression of miR-126 could largely rescue YTHDF2/Ythdf2 depletion-mediated suppression on AML cell growth/proliferation and leukemogenesis, indicating that miR-126 is a functionally important target of YTHDF2 in AML. Overall, our studies not only reveal a previously unappreciated YTHDF2/miR-126 axis in AML and highlight the therapeutic potential of targeting this axis for AML treatment, but also suggest that m6A plays a role in pre-miRNA processing that contributes to tumorigenesis.

3.
Methods Enzymol ; 692: 231-247, 2023.
Artículo en Inglés | MEDLINE | ID: mdl-37925182

RESUMEN

MicroRNAs (miRNAs) are small, non-coding RNA molecules that play a crucial role in gene silencing. The gene-silencing activity of miRNAs depends on their sequences and expression levels. The human RNase III enzyme DICER cleaves miRNA precursors (pre-miRNAs) to produce miRNAs, making it crucial for miRNA production and cellular miRNA functions. DICER is also critical for the gene silencing technology using short-hairpin RNAs (shRNAs), which are cleaved by DICER to generate siRNAs that knockdown target genes. The DICER cleavage assay is an important tool for investigating its molecular mechanisms, which are essential for understanding its functions in miRNA biogenesis and shRNA-based gene silencing technology. The assay involves DICER protein purification, preparation of pre-miRNA and shRNA substrates, and the cleavage assay, using common molecular biology equipment and commercialized reagents that can be applied to other RNA endonucleases.


Asunto(s)
MicroARNs , Humanos , MicroARNs/química , Ribonucleasa III/genética , Ribonucleasa III/química , Ribonucleasa III/metabolismo , ARN Interferente Pequeño/genética , ARN Bicatenario
4.
Chemistry ; 29(39): e202301181, 2023 Jul 11.
Artículo en Inglés | MEDLINE | ID: mdl-37115041

RESUMEN

The structural determinants of the interaction of the G-quadruplex (G4) motif found in precursor miRNA 149 (rG4) with the acridine orange derivative C8 , a G4 ligand stabilizer possessing anticancer activity, and the protein nucleolin (overexpressed in cancer cells) were investigated by Nuclear Magnetic Resonance (NMR) spectroscopy. For the rG4/C8 complex, the results revealed a strong stabilizing interaction between the aromatic core and the iodinated ring of the C8 ligand with the rG4 structure. The NMR study revealed also different interaction patterns between nucleolin and rG4 and nucleolin and rG4/C8 complex. In the absence of the ligand, rG4 establishes interactions with polar residues of the protein while for the rG4/C8 complex, these contacts are mainly established with amino acids that have hydrophobic side chains. However, nucleolin chemical shift perturbation studies in the presence of rG4 or rG4/C8 reveal the same location between domains 1 and 2 of the protein, which suggests that the rG4 and rG4/C8 complex bind in this region. This puzzling structural study opens a new framework to study rG4/ligand/nucleolin complexes that might impact the biogenesis of miRNA 149.


Asunto(s)
G-Cuádruplex , MicroARNs , Humanos , Ligandos , Fosfoproteínas/química , Fosfoproteínas/genética , Fosfoproteínas/metabolismo , Carcinogénesis , Nucleolina
5.
Biomater Adv ; 145: 213267, 2023 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-36599197

RESUMEN

The use of gene-based products, such as DNA or RNA, is increasingly being explored for various innovative therapies. However, the success of these strategies is highly dependent on the effective delivery of these biomolecules to target cells. Therefore, the development of pH-responsive nanoparticles comprises the creation of intelligent delivery systems with high therapeutic efficiency. In this work, the pH-responsiveness of the poly(2-(diisopropylamino)ethyl methacrylate)) (PDPA) block was investigated for the encapsulation and delivery of small RNAs (sRNA) to cancer cells. The pH responsiveness was dependent on the protonation profile of the tertiary amines of PDPA, which directly affected the electrostatic interactions established with RNA. Thus, block copolymers based on poly(oligo(ethylene oxide) methyl ether methacrylate) (POEOMA) and PDPA, POEOMA-b-PDPA, were synthesized by supplemental activator and reducing agent atom transfer radical polymerization (SARA ATRP). The structure of the block copolymers was characterized by size exclusion chromatography and 1H NMR spectroscopy. The copolymers allowed effective complexation of model sRNAs and a pre-miRNA with efficiencies of about 89 % and 91 %, respectively. The characterization by dynamic light scattering revealed that these systems had sizes between 76 and 1375 nm. It was also found that the morphology of the polyplexes depended on the pH, since the preparation at a pH lower than the pKa of the copolymers resulted in spherical but polydisperse particles, while higher pH values resulted in nanoparticles with more homogeneous size, but altered morphology. Moreover, due to pH-responsiveness, it was achieved the release of RNA at pH higher than the pKa of the copolymers, while maintaining its integrity. The polyplexes also showed a high potential to protect RNA from RNases. The transfection of a lung cancer model (A549) and fibroblast cell lines showed that these polyplexes did not cause cell toxicity. In addition, the polyplexes enabled the effective transfection of the A549 cell line with pre-miRNA-29b and miRNA-29b, resulting in a decrease of expression levels of the target DNMT3B gene by approximately 51 % and 47 %, respectively. Overall, the POEOMA-b-PDPA copolymers proved to be a promising strategy for developing responsive delivery systems, that can play a critical role in some diseases, such as cancer, where pH varies between the intra and extracellular environments.


Asunto(s)
MicroARNs , Nanopartículas , Polímeros , Metacrilatos/química , Nanopartículas/química , Concentración de Iones de Hidrógeno
6.
Int J Mol Sci ; 23(24)2022 Dec 18.
Artículo en Inglés | MEDLINE | ID: mdl-36555797

RESUMEN

Mature microRNAs (miRNAs) are single-stranded non-coding RNA (ncRNA) molecules that act in post-transcriptional regulation in animals and plants. A mature miRNA is the end product of consecutive, highly regulated processing steps of the primary miRNA transcript. Following base-paring of the mature miRNA with its mRNA target, translation is inhibited, and the targeted mRNA is degraded. There are hundreds of miRNAs in each cell that work together to regulate cellular key processes, including development, differentiation, cell cycle, apoptosis, inflammation, viral infection, and more. In this review, we present an overlooked layer of cellular regulation that addresses cell dynamics affecting miRNA accessibility. We discuss the regulation of miRNA local storage and translocation among cell compartments. The local amounts of the miRNAs and their targets dictate their actual availability, which determines the ability to fine-tune cell responses to abrupt or chronic changes. We emphasize that changes in miRNA storage and compactization occur under induced stress and changing conditions. Furthermore, we demonstrate shared principles on cell physiology, governed by miRNA under oxidative stress, tumorigenesis, viral infection, or synaptic plasticity. The evidence presented in this review article highlights the importance of spatial and temporal miRNA regulation for cell physiology. We argue that limiting the research to mature miRNAs within the cytosol undermines our understanding of the efficacy of miRNAs to regulate cell fate under stress conditions.


Asunto(s)
MicroARNs , Animales , MicroARNs/genética , MicroARNs/metabolismo , Regulación de la Expresión Génica , ARN Mensajero/genética , Diferenciación Celular , Homeostasis/genética
7.
Nanomedicine ; 45: 102585, 2022 09.
Artículo en Inglés | MEDLINE | ID: mdl-35901958

RESUMEN

Outer membrane vesicles (OMVs) of Escherichia coli as nanoscale spherical vesicles have been recently used in cancer therapy as drug carriers. However, most of them need complicated methods to load cargos. Herein, we proposed an inexpensive and potentially mass-produced method for the preparation of OMV engineered with over-expressed pre-miRNA. In this work, we found that OMV can be released and inherit over-expressed tRNALys-pre-miRNA from mother E. coli that directly used for the tumor therapy. The eukaryotic cells infection experiments revealed that the over-expressed pre-miRNA inside OMV could be released and processed into mature miRNAs with the aid of the camouflage of "tRNA scaffold". Moreover, the group in vivo treated with targeted OMVtRNA-pre-miR-126 obviously inhibited the expression of target oncogenic CXCR4, and significantly restrain the proliferation of breast cancer tissues. Together, these findings indicated that the OMV-based platform is a versatile and powerful strategy for personalized tumor therapy directly and specificity.


Asunto(s)
Vesículas Extracelulares , MicroARNs , Neoplasias , Proteínas de la Membrana Bacteriana Externa , Portadores de Fármacos/metabolismo , Escherichia coli/genética , Humanos , MicroARNs/genética , MicroARNs/metabolismo , Neoplasias/tratamiento farmacológico
8.
Int J Biol Sci ; 18(8): 3237-3250, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35637969

RESUMEN

G protein-coupled receptors (GPCRs) are the largest family of druggable targets, and their biological functions depend on different ligands and intracellular interactomes. Some microRNAs (miRNAs) bind as ligands to RNA-sensitive toll-like receptor 7 to regulate the inflammatory response, thereby contributing to the pathogenesis of cancer or neurodegeneration. It is unknown whether miRNAs bind to angiotensin II (Ang II) type 2 receptor (AGTR2), a critical protective GPCR in cardiovascular diseases, as ligands or intracellular interactomes. Here, screening for miRNAs that bind to AGTR2, we identified and confirmed that the pre-miRNA hsa-let-7a-2 non-competitively binds to the intracellular third loop of AGTR2. Functionally, intracellular hsa-let-7a-2 overexpression suppressed the Ang II-induced AGTR2 effects such as cAMP lowering, RhoA inhibition, and activation of Src homology 2 domain-containing protein-tyrosine phosphatase 1, whereas hsa-let-7a-2 knockdown enhanced these effects. Consistently, overexpressed hsa-let-7a-2 restrained the AGTR2-induced antiproliferation, antimigration, and proapoptosis of cells, and vasodilation of mesenteric arteries. Our findings demonstrated that hsa-let-7a-2 is a novel intracellular partner of AGTR2 that negatively regulates AGTR2-activated signals.


Asunto(s)
MicroARNs , Ligandos , MicroARNs/metabolismo , Receptor de Angiotensina Tipo 2/genética
9.
RNA ; 28(7): 1028-1038, 2022 07.
Artículo en Inglés | MEDLINE | ID: mdl-35487691

RESUMEN

Hairpin-containing pre-miRNAs, produced from pri-miRNAs, are precursors of miRNAs (microRNAs) that play essential roles in gene expression and various human diseases. Current qPCR-based methods used to quantify pre-miRNAs are not effective to discriminate between pre-miRNAs and their parental pri-miRNAs. Here, we developed the intramolecular ligation method (iLIME) to quantify and sequence pre-miRNAs specifically. This method utilizes T4 RNA ligase 1 to convert pre-miRNAs into circularized RNAs, allowing us to design PCR primers to quantify pre-miRNAs, but not their parental pri-miRNAs. In addition, the iLIME also enables us to sequence the ends of pre-miRNAs using next-generation sequencing. Therefore, this method offers a simple and effective way to quantify and sequence pre-miRNAs, so it will be highly beneficial for investigating pre-miRNAs when addressing research questions and medical applications.


Asunto(s)
MicroARNs , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , MicroARNs/metabolismo , Reacción en Cadena en Tiempo Real de la Polimerasa
10.
J Pharm Biomed Anal ; 215: 114757, 2022 Jun 05.
Artículo en Inglés | MEDLINE | ID: mdl-35462282

RESUMEN

Let-7e precursor microRNA has the potential to adopt a G-quadruplex (rG4) structure and recently, its roles in oncology have been the focus of much attention, as it is now known that let-7e pre-miRNA is frequently dysregulated in cancers. Therefore, it is crucial to unveil and fully characterize its ability to adopt a rG4 structure, which could be stabilized or destabilized by small molecules and proteins such as nucleolin, a protein that is deeply associated with miRNA biogenesis. Herein, by combining a set of different methods such as circular dichroism (CD), nuclear magnetic resonance (NMR), UV spectroscopy (thermal difference spectra (TDS) and isothermal difference spectra (IDS)) and polyacrylamide gel electrophoresis (PAGE), we demonstrate the formation of the rG4 structure found in let-7e pre-miRNA sequence in the presence of K+ (5'-GGGCUGAGGUAGGAGG-3'). The ability of eight small molecules (or ligands) to bind to and stabilize this rG4 structure was also fully assessed. The dissociation constants for each RNA G-quadruplex/ligand complex, determined by surface plasmon resonance (SPR), ranged in the 10-6 to 10-9 M range. Lastly, the binding of the rG4 structure to nucleolin in the presence and absence of ligands was evaluated via CD, SPR, PAGE and confocal microscopy. The small molecules 360 A and PDS demonstrated attractive properties to targetthe rG4 structure of let-7e pre-miRNA and control its biology. Our findings also highlighted that the interaction of TMPyP4 with the G-quadruplex of let-7e precursor miRNA could block the formation of the complex between the rG4 and nucleolin. Overall, this study introduces an approach to target the rG4 found in let-7e pre-miRNA which opens up a new opportunity to control the microRNA biogenesis.


Asunto(s)
G-Cuádruplex , MicroARNs , Ligandos , MicroARNs/metabolismo , Fosfoproteínas , Proteínas de Unión al ARN/genética , Proteínas de Unión al ARN/metabolismo , Nucleolina
11.
Mol Ther Nucleic Acids ; 27: 165-174, 2022 Mar 08.
Artículo en Inglés | MEDLINE | ID: mdl-34976435

RESUMEN

Selective targeting of biologically relevant RNAs with small molecules is a long-standing challenge due to the lack of clear understanding of the binding RNA motifs for small molecules. The standard SELEX procedure allows the identification of specific RNA binders (aptamers) for the target of interest. However, more effort is needed to identify and characterize the sequence-structure motifs in the aptamers important for binding to the target. Herein, we described a strategy integrating high-throughput (HT) sequencing with conventional SELEX followed by bioinformatic analysis to identify aptamers with high binding affinity and target specificity to unravel the sequence-structure motifs of pre-miRNA, which is essential for binding to the recently developed new water-soluble small-molecule CMBL3aL. To confirm the fidelity of this approach, we investigated the binding of CMBL3aL to the identified motifs by surface plasmon resonance (SPR) spectroscopy and its potential regulatory activity on dicer-mediated cleavage of the obtained aptamers and endogenous pre-miRNAs comprising the identified motif in its hairpin loop. This new approach would significantly accelerate the identification process of binding sequence-structure motifs of pre-miRNA for the compound of interest and would contribute to increase the spectrum of biomedical application.

12.
Methods Mol Biol ; 2257: 167-174, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-34432278

RESUMEN

MicroRNA (miRNA) studies have been one of the most popular research areas in recent years. Although thousands of miRNAs have been detected in several species, the majority remains unidentified. Thus, finding novel miRNAs is a vital element for investigating miRNA mediated posttranscriptional gene regulation machineries. Furthermore, experimental methods have challenging inadequacies in their capability to detect rare miRNAs, and are also limited to the state of the organism under examination (e.g., tissue type, developmental stage, stress-disease conditions). These issues have initiated the creation of high-level computational methodologies endeavoring to distinguish potential miRNAs in silico. On the other hand, most of these tools suffer from high numbers of false positives and/or false negatives and as a result they do not provide enough confidence for validating all their predictions experimentally. In this chapter, computational difficulties in detection of pre-miRNAs are discussed and a machine learning based approach that has been designed to address these issues is reviewed.


Asunto(s)
Biología Computacional , MicroARNs/genética , Aprendizaje Automático
13.
Vavilovskii Zhurnal Genet Selektsii ; 26(8): 819-825, 2022 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-36694714

RESUMEN

MicroRNAs (miRNAs) are small non-coding RNAs that regulate gene expression at the post-transcriptional level in the cytoplasm and play an important role in a wide range of biological processes. Recent studies have found that the miRNA sequences are presented not only in the cytoplasm, but also in the mitochondria. These miRNAs (the so-called mitomiRs) may be the sequences of nuclear or mitochondrial origin; some of them are involved in regulation of the mitochondrial gene functions, while the role of others is still unknown. The identification of nucleotide signals, which are unique to mitomiRs, may help to determine this role. We formed a dataset that combined the experimentally discovered mitomiRs in human, rat and mouse. To isolate signals that may be responsible for the mitomiRs' functions or for their translocation from or into mitochondria a context analysis was carried out for the sequences. For three species in the group mitomiRs/non-mitomiRs and the group of all miRNAs from the miRBase database statistically overrepresented 8-letter motifs were identified (p-value < 0.01 with Bonferroni correction for multiple comparisons), for these motifs the patterns of the localization in functionally important regions for different types of miRNAs were found. Also, for the group mitomiRs/non-mitomiRs we found the statistically significant features of the miRNA nucleotide context near the Dicer and Drosha cleavage sites (Pearson's χ2 test of independence for the first three positions of the miRNA, p-value < 0.05). The observed nucleotide frequencies may indicate a more homogeneous pri-miRNA cleavage by the Drosha complex during the formation of the 5' end of mitomiRs. The obtained results can help to determine the role of the nucleotide signals in the origin, processing, and functions of the mitomiRs.

14.
Trends Genet ; 38(4): 379-394, 2022 04.
Artículo en Inglés | MEDLINE | ID: mdl-34728089

RESUMEN

Alterations in microRNAs (miRNAs) expression are causative in the initiation and progression of human cancers. The molecular events responsible for the widespread differential expression of miRNAs in malignancy are exemplified by their location in cancer-associated genomic regions, epigenetic mechanisms, transcriptional dysregulation, chemical modifications and editing, and alterations in miRNA biogenesis proteins. The classical miRNA function is synonymous with post-transcriptional repression of target protein genes. However, several studies have reported miRNAs functioning outside this paradigm and some of these novel modes of regulation of gene expression have been implicated in cancers. Here, we summarize key aspects of miRNA involvement in cancer, with a special focus on these lesser-studied mechanisms of action.


Asunto(s)
MicroARNs , Neoplasias , Epigénesis Genética/genética , Expresión Génica , Humanos , MicroARNs/genética , Neoplasias/genética
15.
Eur J Pharm Sci ; 169: 106093, 2022 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-34922315

RESUMEN

One of the most significant challenges in capturing and detecting biomarkers is the choice of an appropriate biomolecular receptor. Recently, RNA G-quadruplexes emerged as plausible receptors due to their ability to recognize with high-affinity proteins. Herein, we have unveiled and characterized the capability of the precursor microRNA 149 to form a G-quadruplex structure and determined the role that some ligands may have in its folding and binding capacity to nucleolin. The G-quadruplex formation was induced by K+ ions and stabilized by ligands, as demonstrated by nuclear magnetic resonance and circular dichroism experiments. Surface plasmon resonance measurements showed a binding affinity of precursor microRNA 149 towards ligands in the micromolar range (10-5-10-6 M) and a strong binding affinity to nucleolin RNA-binding domains 1 and 2 (8.38 × 10-10 M). Even in the presence of the ligand PhenDC3, the binding remains almost identical and in the same order of magnitude (4.46 × 10-10 M). The molecular interactions of the RNA G-quadruplex motif found in precursor miRNA 149 (5'-GGGAGGGAGGGACGGG- 3') and nucleolin RNA-binding domains 1 and 2 were explored by means of molecular docking and molecular dynamics studies. The results showed that RNA G-quadruplex binds to a cavity between domains 1 and 2 of the protein. Then, complex formation was also evaluated through polyacrylamide gel electrophoresis. The results suggest that precursor microRNA 149/ligands and precursor microRNA 149/nucleolin RNA-binding domains 1 and 2 form stable molecular complexes. The in vitro co-localization of precursor microRNA 149 and nucleolin in PC3 cells was demonstrated using confocal microscopy. Finally, a rapid and straightforward microfluidic strategy was employed to check the ability of precursor microRNA 149 to capture nucleolin RNA-binding domains 1 and 2. The results revealed that precursor microRNA 149 can capture nucleolin RNA-binding domains 1 and 2 labeled with Fluorescein 5-isothiocyanate in a concentration-dependent manner, but PhenDC3 complexation seems to decrease the ability of precursor microRNA 149 to capture the protein. Overall, our results proved the formation of the G-quadruplex structure in the precursor microRNA 149 and the ability to recognize and detect nucleolin. This proof-of-concept study could open up a new framework for developing new strategies to design improved molecular receptors for capture and detection of nucleolin in complex biological samples.


Asunto(s)
G-Cuádruplex , MicroARNs , Fosfoproteínas , Proteínas de Unión al ARN , Línea Celular , Humanos , MicroARNs/genética , Simulación del Acoplamiento Molecular , Fosfoproteínas/genética , Proteínas de Unión al ARN/genética , Nucleolina
16.
Infect Genet Evol ; 96: 105139, 2021 12.
Artículo en Inglés | MEDLINE | ID: mdl-34798320

RESUMEN

A small non-coding, evolutionarily conserved regulatory RNA molecule known as microRNA (miRNA) regulates various cellular activities and pathways. MicroRNAs remain evolutionarily conserved in different species of same taxa. They are present in all organisms including viruses. Viral miRNAs are small, less conserved and less stable and have higher negative minimal folding free energy than miRNAs of different organisms. The size of viral precursor miRNA is approximately 60-119 nucleotides in length. The structure of the mature miRNA sequences is predicted by using higher negative MFE (ΔG) value. Rous sarcoma Virus (RSV), named after its inventor Peyton Rous, has been known for causing tumors in the chicken for which it is known as an oncogenic retrovirus. Using specific criteria we have predicted 5 potential miRNAs in RSV which targeted 8 tumor suppressor genes in Gallus gallus. This study aims to predict the potential miRNAs, secondary structures and their targets for better understanding of the regulatory network of Rous sarcoma virus miRNA in forming sarcoma.


Asunto(s)
Pollos , Genes Supresores de Tumor/fisiología , MicroARNs/genética , Enfermedades de las Aves de Corral/virología , ARN Viral/genética , Virus del Sarcoma de Rous/genética , Sarcoma Aviar/virología , Animales
17.
RNA Biol ; 18(sup2): 730-737, 2021 11 12.
Artículo en Inglés | MEDLINE | ID: mdl-34592896

RESUMEN

Exportin 5 (Exp5, XPO5) is a nuclear export factor that functions in the microRNA (miRNA) biogenesis pathway to transport precursor miRNAs (pre-miRNAs) from the nucleus to the cytoplasm. Most of our current understanding of the Exp5 and pre-miRNA interaction is based on the investigation of how Exp5 binds to human pre-miR-30a (pre-miR-30 for short). As there are hundreds of human miRNA genes, how representative pre-miR-30 is, whether or how Exp5 interacts with distinct cargoes differentially, or whether Exp5 regulates miRNA expression, is unknown. Here we examined and compared the interactions between Exp5 and 157 human pre-miRNAs. We found that Exp5 binds distinct pre-miRNAs with modest variations in efficiencies, with the 3' overhang and the apical loop in pre-miRNAs being the two major discriminating factors. Exp5 binding efficiencies do not significantly correlate with endogenous miRNA expression, suggesting that Exp5 activity does not contribute to differential miRNA expression in vivo. Nonetheless, in human cells with reduced Exp5 levels, preferential Exp5 binding correlated with miRNA expression changes. Thus, our study provides a global picture of how Exp5 interacts with human pre-miRNAs and its role in regulating miRNA expression.Abbreviations: Exp5: Exportin 5; miRNA: microRNA; pri-miRNA: primary microRNA; pre-miRNA: precursor microRNA; nt: nucleotide.


Asunto(s)
Carioferinas/metabolismo , MicroARNs/genética , Precursores del ARN/genética , Línea Celular , Ensayo de Cambio de Movilidad Electroforética , Regulación de la Expresión Génica , Humanos , MicroARNs/química , MicroARNs/metabolismo , Conformación de Ácido Nucleico , Unión Proteica , Precursores del ARN/química , Precursores del ARN/metabolismo , Transporte de ARN , Proteínas de Unión al ARN/metabolismo , Proteínas Recombinantes
18.
Methods Enzymol ; 658: 49-72, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34517959

RESUMEN

RNAs from various cells and tissues are modified in nearly 200 chemically distinct ways. These modifications can be deposited either on the 5' or 3' ends, or internally on the nucleobases or sugar backbone. 5'-end modifications are crucial for protecting RNAs from untimely degradation/processing, regulating their cellular functions, or discriminating endogenous RNAs from pathogenic RNAs. 5'-end phospho-methylation is a remarkable RNA modification that is enzymatically deposited either on the γ-phosphate of nascent triphosphorylated RNAs by human BCDIN3/MePCE, or on the α-phosphate of processed monophosphorylated RNAs by human BCDIN3D. These 5'-phospho-methyltransferases are part of the BIN3 family of O-methyltransferases conserved from S. pombe to humans and play important cellular and biological roles, many of which await further elucidation. Here, we quickly recapitulate historical methods for the detection of 5'-end phospho-methyl modifications, and focus more specifically on a method that can be used to detect and quantify α-monophosphate methylation from as low as 10-100ng of total RNA from cells or tissues. This method is important for deciphering the roles of BCDIN3D and its homologs across species, as well as serves as starting point for the development of new methods for detection of 5'-end modifications.


Asunto(s)
Metiltransferasas , ARN , Humanos , Metilación , Metiltransferasas/metabolismo , Procesamiento Postranscripcional del ARN
19.
Genes (Basel) ; 12(8)2021 08 21.
Artículo en Inglés | MEDLINE | ID: mdl-34440454

RESUMEN

MicroRNAs (miRNAs) are a kind of short non-coding ribonucleic acid molecules that can regulate gene expression. The computational identification of plant miRNAs is of great significance to understanding biological functions. In our previous studies, we have put firstly forward and further developed a set of knowledge-based energy features to construct two plant pre-miRNA prediction tools (plantMirP and riceMirP). However, these two tools cannot be used for miRNA prediction from NGS (Next-Generation Sequencing) data. In addition, for further improving the prediction performance and accessibility, plantMirP2 has been developed. Based on the latest dataset, plantMirP2 achieves a promising performance: 0.9968 (Area Under Curve, AUC), 0.9754 (accuracy), 0.9675 (sensitivity) and 0.9876 (specificity). Additionally, the comparisons with other plant pre-miRNA tools show that plantMirP2 performs better. Finally, the webserver and stand-alone version of plantMirP2 are available.


Asunto(s)
Biología Computacional/instrumentación , MicroARNs/genética , Precursores del ARN/genética , Programas Informáticos , Algoritmos , MicroARNs/aislamiento & purificación , Plantas/genética , Precursores del ARN/aislamiento & purificación , Máquina de Vectores de Soporte
20.
Int J Mol Sci ; 22(16)2021 Aug 20.
Artículo en Inglés | MEDLINE | ID: mdl-34445712

RESUMEN

Pre-miRNA-377 is a hairpin-shaped regulatory RNA associated with heart failure. Here, we use single-molecule optical tweezers to unzip pre-miRNA-377 and study its stability and dynamics. We show that magnesium ions have a strong stabilizing effect, and that sodium ions stabilize the hairpin more than potassium ions. The hairpin unfolds in a single step, regardless of buffer composition. Interestingly, hairpin folding occurs either in a single step (type 1) or through the formation of intermediates, in multiple steps (type 2) or gradually (type 3). Type 3 occurs only in the presence of both sodium and magnesium, while type 1 and 2 take place in all buffers, with type 1 being the most prevalent. By reducing the size of the native hairpin loop from fourteen to four nucleotides, we demonstrate that the folding heterogeneity originates from the large size of the hairpin loop. Further, while efficient pre-miRNA-377 binders are lacking, we demonstrate that the recently developed C2 ligand displays bimodal activity: it enhances the mechanical stability of the pre-miRNA-377 hairpin and perturbs its folding. The knowledge regarding pre-miRNA stability and dynamics that we provide is important in understanding its regulatory function and how it can be modulated to achieve a therapeutic effect, e.g., in heart failure treatment.


Asunto(s)
MicroARNs/ultraestructura , Pliegue del ARN/genética , Imagen Individual de Molécula/métodos , Insuficiencia Cardíaca/genética , Humanos , MicroARNs/genética , Nanotecnología , Conformación de Ácido Nucleico , Pinzas Ópticas , ARN/química , Pliegue del ARN/fisiología , Procesamiento Postranscripcional del ARN/genética , Procesamiento Postranscripcional del ARN/fisiología
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