Search Results (265)

R-loops, three-stranded nucleic acid structures formed by an RNA-DNA hybrid, have emerged as important regulators of transcription and genome stability. Although advances in high-throughput sequencing have revealed widespread R-loop landscapes, platform-specific biases hinder the identification of conserved R-loops in specific cell types. Mouse embryonic stem cells, which are transcriptionally active, provide an ideal system for investigating the potential roles of stable R-loops in RNA biology. Here, we integrated 13 independent R-loop profiling datasets from four experimental platforms to define 27,950 Common R-loop regions in mouse embryonic stem cells and characterized their chromatin environment and associated biological functions. Common R-loop regions were reproducibly detected across methods and were preferentially localized to promoter-proximal and genic regions enriched in CpG islands. Genes associated with Common R-loops were highly and stably expressed, showing strong functional enrichment in RNA metabolic processes such as mRNA processing, RNA splicing, and ribonucleoprotein complex biogenesis. Chromatin state analysis revealed that Common R-loops are enriched in transcriptionally active and regulatory contexts. Sequence feature analysis further identified GC skew as a prominent signature of Common R-loops, particularly within transcribed chromatin states. Transcription factor motif analyses have identified distinct regulatory environments in Common R-loop regions, including pluripotency-associated OCT4-SOX2-TCF-NANOG motifs in enhancers, CTCF motifs in open chromatin, and YY1 motifs in promoters. Together, this study provides the first integrated analysis of conserved R-loop regions in mouse embryonic stem cells, revealing their preferential localization at regulatory loci linked to RNA metabolism and highlighting R-loops as structural and functional nodes in RNA biology. Full article

Approaches to delivering gene editing tools in the form of ribonucleoproteins may provide a safety advantage over the delivery of nucleic acids encoding ribonucleoproteins. Virus-based vectors are widely used as a delivery platform. However, the persistence of viral exogenous nucleic acids can cause increased genotoxicity. Virus-like particles (VLPs) do not contain an expression cassette and can act as a platform for the delivery of ready-made ribonucleoprotein complexes. The absence of nucleic acids in VLPs eliminates the risk of insertional mutagenesis compared to widely used lentiviruses or adeno-associated viruses. Therefore, we used VLPs to deliver the ribonucleoprotein complex MmCas12m–TadDE to disrupt the HIV-1 gag gene start codon. We detected VLP morphogenesis using electron microscopy. We confirmed the incorporation of MmCas12m–TadDE into VLPs. We achieved an editing efficiency of about 9% in some cases with minimal off-target effects, which confirms the prospect of using VLPs as a platform for delivering genomic editing tools. Full article

Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) system is a simple and powerful tool, which enables gene knockout or insertion of new gene cassettes. This method has been applied to various plants and is used for crop improvement. Cultivated strawberry (Fragaria× ananassa), a member of the Rosaceae family, is a high-value horticultural crop. However, its complex octoploid genome poses challenges for precise genome editing in polyploids. This study aimed to establish a protoplast-based, DNA-free genome-editing approach in the cultivated octoploid strawberry. We optimized the culture conditions and enzyme combinations to enable efficient protoplast isolation from the fully developed leaves. The highest protoplast yield was obtained with a Murashige and Skoog medium containing 1% sucrose and 2 mg/L 6-benzylaminopurine (BA), along with enzymatic digestion using 2% Viscozyme, 1% Celluclast, and 1% Pectinex. Transient transfection conditions were optimized using a green fluorescence protein (GFP) plasmid with the highest expression efficiency (up to 52.5%) observed using 40% PEG 4000 and 20 min incubation. Under these conditions, Cas9 ribonucleoproteins (RNPs) targeting the FaPDS and FaPG1 genes were introduced, and guide RNA (gRNA) screening was conducted by targeted deep sequencing. In conclusion, this study successfully demonstrated protoplast isolation and DNA-free CRISPR/Cas9 genome editing in cultivated strawberry. The optimized protoplast-based system provides a valuable platform for functional genomics and molecular breeding efforts in octoploid strawberries. Full article

CRISPR-Cas9 technology has opened new perspectives in genome editing of clonally, asexually propagated and polyploid plants by enabling multiple allelic gene edits. Traditional Agrobacterium- and particle bombardment-mediated transformations, which rely on integration of gene-editing transgene cassettes, have been efficiently applied to several plants; however, concerns about the acceptability of resultant edited transgenic genotypes make these methods less attractive for vegetatively propagated crops. We leveraged and optimized the CRISPR-Cas9/sgRNA-RNPs system for delivery into protoplasts of the hexaploid sweetpotato cultivar PI-318846, targeting eukaryotic translation initiation factor isoform 4E genes to enhance resistance to SPFMV potyviruses. To evaluate the efficiency of pre-assembled Cas9/sgRNA-RNP in sweetpotato transfection, single guide RNAs were designed to target putative host susceptibility genes: IbeIF4E, IbeIF(iso)4E, and IbCBP. Freshly isolated leaf protoplasts were subjected to CRISPR-CAS9-RNP PEG-mediated transfection under different parameters. Sweetpotato regenerants screened using PCR-RE-T7 assay, sequencing, and Inference CRISPR Edit analyses of target-site amplicons revealed the most efficient editing conditions utilizing 25% PEG with a 3:1 (15 µg:45 µg) ratio of Cas9/sgRNA-RNP for 25 min and 48 h incubation period. Different allelic InDels were obtained with editing efficiencies of 10–20% in regenerated plantlets, demonstrating that PEG-mediated CRISPR-RNP transfection system is key for advancing DNA-free editing tools in polyploid and vegetatively propagated crops. Full article

The phenomenon of transgene silencing was first observed shortly after the generation of the initial transgenic plants. The vast body of experimental data accumulated since then constitutes an invaluable resource for dissecting the mechanisms of epigenetic gene regulation. Silencing operates at either the transcriptional (TGS) or post-transcriptional (PTGS) level and is predominantly mediated by small interfering RNAs (siRNAs). Although these two epigenetic pathways involve distinct sets of proteins and enzymes, they share fundamental mechanistic features: the generation of double-stranded RNA (dsRNA), its processing into siRNAs by DICER-LIKE (DCL) enzymes, and the assembly of an Argonaute-centered effector ribonucleoprotein complex (RISC). Guided by sequence-specific siRNAs, this complex identifies complementary target sequences with high precision. A comprehensive understanding of these regulatory pathways enables the targeted induction or suppression of specific plant genes. This review traces the history of experimental findings regarding the loss of recombinant gene activity in transformants and their progeny, which collectively established the foundation for elucidating the molecular mechanisms of transgene silencing. Full article

Background: Diabetic nephropathy (DN) is largely driven by transforming growth factor-β1 (TGF-β1)-mediated fibrosis. Clustered regularly interspaced short palindromic repeats (CRISPR)-associated protein 9 (Cas9) ribonucleoprotein (RNP) complexes offer precise gene disruption, yet effective non-viral delivery remains a challenge. This study developed cationic lipid-based hybrid nanostructured lipid carriers (NLCs) for intracellular delivery of TGFB1-targeting RNP as an early-stage platform for DN gene modulation. Methods: A single-guide RNA (sgRNA) targeting human TGFB1 was assembled with Cas9 protein (1:1 and 1:2 molar ratios). Hybrid NLCs comprising squalene, glyceryl trimyristate, and the cationic lipid 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) were formulated via optimized emulsification–sonication to achieve sub-100 nm particles. Physicochemical properties, including polydispersity index (PDI), were assessed via dynamic light scattering (DLS), while silencing efficacy in HEK293T cells was quantified using quantitative reverse transcription PCR (RT-qPCR) and enzyme-linked immunosorbent assay (ELISA). Results: Optimized NLCs achieved hydrodynamic diameters of 65–99 nm (PDI < 0.5) with successful RNP complexation. The 1:2 Cas9:sgRNA formulation produced the strongest gene-editing response, reducing TGFB1 mRNA by 67% (p < 0.01) compared with 39% for the 1:1 ratio. This translated to a significant reduction in TGF-β1 protein (p < 0.05) within 24 h. Conclusions: DOTAP-based hybrid NLCs enable efficient delivery of CRISPR–Cas9 RNP and achieve significant suppression of TGFB1 expression at both transcriptional and protein levels. These findings establish a promising non-viral platform for upstream modulation of profibrotic signaling in DN and support further evaluation in kidney-derived cells and in vivo renal models. Full article

The SARS-CoV-2 nucleocapsid protein (Np) plays multifunctional roles in the viral life cycle. By interacting with host cellular proteins, Np regulates viral RNA transcription, replication, and immune evasion. It controls genome packaging and counteracts host RNA interference mediated antiviral responses through its RNA binding activity. Previous studies revealed a physical interaction between Np and DDX3X, a human DEAD-box RNA helicase that facilitates the replication of several viruses. This interaction enhances Np affinity for double-stranded RNA and inhibits DDX3X helicase activity. Since Np-RNA binding activity promotes ribonucleoprotein complex formation, targeting this interaction is a promising antiviral strategy. We generated truncated protein variants to define interaction regions between Np and DDX3X. Using AlphaFold modelling, we identified RecA2 as the key DDX3X domain involved in Np binding. Finally, to disrupt Np-RNA complex formation, we screened a small molecule library of putative binders of Np N-terminal region and identified two candidate inhibitors for further development. Full article

The rapid evolution of CRISPR/Cas technology has transformed genome editing across biological systems in which zebrafish have emerged as a powerful vertebrate model for functional genomics and disease research. Due to its transparency, genetic similarity to humans, and suitability for large-scale screening, zebrafish is an appropriate system for translating molecular discoveries into biomedical and environmental applications. Thereby, this review highlights the recent progress in zebrafish gene editing, targeting innovations in ribonucleoprotein delivery, PAM-flexible Cas variants, and precision editors. These approaches have greatly improved editing accuracy, reduced mosaicism, and enabled efficient F0 phenotyping. In the near future, automated microinjections, optimized guide RNA design, and multi-omics validation pipelines are expected to enhance reproducibility and scalability. Although recent innovations such as ribonucleoprotein delivery, PAM-flexible Cas variants, and precision editors have expanded the zebrafish genome-editing toolkit, their benefits are often incremental and context-dependent. Mosaicism, allele complexity, and variable germline transmission remain common, particularly in F0 embryos. Precision editors enable defined nucleotide changes but typically exhibit modest efficiencies and locus-specific constraints in zebrafish. Consequently, rigorous validation, standardized workflows, and careful interpretation of F0 phenotypes remain essential. This review critically examines both the capabilities and limitations of current zebrafish gene-editing technologies, emphasizing experimental trade-offs, reproducibility challenges, and realistic use cases. Full article

RNA maturation, particularly splicing, depends on coordinated actions of RNA-binding proteins through post-transcriptional processing and constitutes a central mechanism of gene regulation. Aberrant splicing is associated with various diseases, including cancer. Here, we show that the CoREST complex, in coordination with c-MYC, transcriptionally regulates a subset of RNA processing genes, including those encoding essential small nuclear ribonucleoproteins (snRNPs) required for proper spliceosome function. Genetic depletion or the pharmacological inhibition of the CoREST complex in melanoma cells disrupted spliceosome activity, leading to widespread changes in alternative mRNA isoform expression and reduced cell viability. These splicing alterations were associated with changes in the 2′-O-methylation (Nm) of U1 snRNA, a modification critical for spliceosomal function. The ectopic expression of the nucleolar protein NOLC1, a downstream target of the CoREST complex and known for its role in ribosomal RNA processing, partially rescued viability, splicing patterns, and U1 snRNA methylation in CoREST-deficient melanoma cells. Conversely, NOLC1 depletion sensitized melanoma cells to the MEK inhibitor trametinib, a clinical drug approved for treating advanced melanoma. Together, these findings uncover a novel CoREST-NOLC1 axis which is a transcriptional regulatory mechanism playing a significant role in RNA splicing, highlighting that NOLC1 is a downstream effector of the CoREST complex and a potential therapeutic target for melanoma treatment. Full article

Influenza A virus (IAV) poses a major threat to global public health, exerting immense pressure on human health and the economy. The IAV nucleoprotein (NP) is an ideal target for antiviral drug development. Through Mini-genome and Surface Plasmon Resonance assays, this study discovered and verified that mycophenolic acid methyl ester (MAE), a secondary metabolite produced by the marine algal-associated fungus Phaeosphaeria spartinae, can target the viral nucleoprotein to exert anti-IAV activity. Pull-down assays and immunofluorescence have revealed that MAE blocks the nuclear import of viral ribonucleoprotein complexes (vRNP) by interfering with the interaction between NP and IMP-α. It also affects the vRNP assembly process by regulating NP oligomerization and the interaction between NP and PB2. In addition, Sandwich ELISA and Electron Microscopy experiments showed that MAE can also inactivate viral particles to reduce the risk of infection. Comprehensive research results indicate that MAE exerts its effects by inhibiting the viral NP protein, which has laid an important foundation for the development of marine-derived NP-targeted drugs. Full article

Pre-mRNA splicing is catalyzed by the ribonucleoprotein (RNP) complex known as the spliceosome. The spliceosomes are dynamic and undergo constant rearrangement, leading to the formation of the different spliceosomal complexes A, B, B^act, C, C*, and P. Isolation of the spliceosomal complex at a specific intermediate stage requires a means to enrich it. This study describes a strategy for studying intermediate spliceosomal complexes by combining BioID with splicing assays. The MINX splicing substrate with a mutation at the 3′ splice site was utilized to arrest and capture the spliceosomal C* complex before the second catalytic step of splicing. The splicing substrate also contains binding sites for the MS2 coat protein, which facilitates the pull-down of assembled complex by FLAG-MS2-tagged RNP immunoprecipitation and determines the captured proximal proteins by mass spectrometry. Full article

Introduction: Bovine leukemia virus is a single-stranded RNA virus that targets B cell CD5⁺ lymphocytes in cattle. Only a tiny percentage of individuals develop malignant lymphoproliferative disorders, while most remain healthy carriers or experience persistent lymphocytosis. The exact mechanisms leading to lymphoma development are complex and not fully understood. RNA-seq analysis of cows’ peripheral blood leukocytes (PBLs) with and without Bovine leukemia virus (BLV) antibodies was conducted to gain a deeper understanding of molecular events beyond BLV infection. Method: Eighteen samples were selected, and their RNA was sequenced. For gene expression analysis and protein–protein network interactions, three groups were selected, including healthy negative samples (CT, n = 7), asymptomatic carriers (AC, n = 5), and persistent lymphocytosis (PL, n = 6), to provide the differentially expressed gene (DEG) and protein–protein interaction network (PPIN) outputs. Results: Our results demonstrated that in comparison to CT, ACs upregulated TLR7 and transcription activation factors. In the CT vs. PL group, MHC class II, transcription activation factors, and anti-inflammatory cytokines increased, while the acute-phase proteins, antiviral receptors, and inflammatory cytokines decreased. Additionally, antiviral receptors, acute-phase proteins, and inflammatory receptors were downregulated in the PL versus the AC groups. Moreover, PPINs analysis suggested that nuclear receptor corepressor 1 (NCOR1), serine/arginine repetitive matrix 2 (SRRM2), LUC7 like 3 pre-mRNA splicing factor (LUC7L3), TWIST neighbor (TWISTNB), U6 small nuclear RNA and mRNA degradation associated (LSM4), eukaryotic translation elongation factor 2 (EEF2), ubiquitin C (UBC), CD74, and heterogeneous nuclear ribonucleoprotein A2/B1 (HNRNP A2B1) are possible hub gene candidates in the PL group. Conclusions: Our results suggest that innate and cellular immune responses are more loose in severe BLV infectious conditions, while the PPINs revealed that new protein interactions are necessary for oncogenesis. Full article

Background/Objectives: Colorectal cancer (CRC) remains a leading cause of cancer-related deaths, with notable sex-specific differences in its incidence, diagnosis, and outcomes. Our previous work identified casein kinase 2 alpha (CK2α) as being capable of impairing DNA mismatch repair (MMR) via phosphorylation of MLH1, thereby increasing the tumor mutational burden. This study aimed to investigate sex-specific differences in CK2α protein expression in CRC. Methods: Immunohistochemical (IHC) analysis was performed on 161 CRC tumors and adjacent normal tissues to quantify the CK2α protein levels. A multi-cohort meta-analysis of proteomic and clinical data was conducted to validate our findings and assess the correlations with age, sex, and relevant signaling pathways. Results: Female CRC patients exhibited significantly higher CK2α expression than male patients, which was confirmed in two independent cohorts. Additionally, CK2α expression was positively correlated with age in female but not male patients. Cross-cohort correlation analyses linked CK2α levels with key proteins involved in estrogen receptor signaling and aging, including DEAD-box helicase 5 (DDX5), histone deacetylase 1 (HDAC1), proliferating cell nuclear antigen (PCNA), prohibitin-2 (PHB2), H/ACA ribonucleoprotein complex subunit 2 (NHP2), and dual-specificity mitogen-activated protein kinase kinase 3 (MAP2K3). Conclusions: CK2α is significantly overexpressed in the tumor tissue of female CRC patients and shows a strong age-related correlation. These findings suggest a sex- and age-specific regulatory mechanism potentially influenced by estrogen signaling or menopause. Such dimorphisms underscore the need for sex-specific strategies in CRC biomarker development and therapy. Full article

Prime editing (PE) has emerged as a transformative genome editing technology, enabling precise base substitutions, insertions, and deletions without inducing double-strand DNA breaks (DSBs). However, its application in zebrafish remains limited by low efficiency. Here, we leveraged PE7, a state-of-the-art PE system, combined with La-accessible prime editing guide RNAs (pegRNAs), to enhance editing efficiency in zebrafish. By co-incubating PE7 protein with La-accessible pegRNAs to form ribonucleoprotein (RNP) complexes and microinjecting these complexes into zebrafish embryos, we achieved up to 15.99% editing efficiency at target loci—an improvement of 6.81- to 11.46-fold over PE2. Additionally, we observed 16.60% 6 bp insertions and 13.18% 10 bp deletions at the adgrf3b locus, representing a 3.13-fold increase over PE2. Finally, we used PE to introduce desired edits at the tyr locus, successfully generating zebrafish with the tyr P302L mutation that exhibited melanin reduction. These findings demonstrate that PE7 significantly enhances prime editing efficiency in fish, providing novel tools for functional gene studies and genetic breeding in aquatic species. Full article

The recent discovery of Orthonairovirus songlingense (SGLV) and Norwavirus beijiense (BJNV) in China has raised significant concern due to their potential to cause severe human disease. However, little is known about the structural features and function of their nucleoproteins, which play a key role in the viral life cycle. By combining small-angle X-ray scattering (SAXS) data and AlphaFold 3 simulations, we reconstructed the BJNV and SGLV nucleoprotein structures for the first time. The SGLV and BJNV nucleoproteins have structures that are broadly similar to those of Orthonairovirus haemorrhagiae (CCHFV) nucleoproteins despite low sequence similarity. Based on structural analysis, several residues located in the positively charged region of BJNV and SGLV nucleoproteins have been indicated to be important for viral RNA binding. A positively charged RNA-binding crevice runs along the interior of the SGLV and BJNV ribonucleoprotein complex (RNP), shielding the viral RNA. Despite the high structural similarity between SGLV and BJNV nucleoprotein monomers, their RNPs adopt distinct conformations. These findings provide important insights into the molecular mechanisms of viral genome packaging and replication in these emerging pathogens. Also, our work demonstrates that experimental SAXS data can validate and improve predicted AlphaFold 3 structures to reflect their solution structure and also provides the first low-resolution structures of the BJNV and SGLV nucleoproteins for the future development of POC tests, vaccines, and antiviral drugs. Full article