Search Results (536)

Intrinsically disordered regions enable transcription factors (TFs) to undergo structural changes upon ligand binding, facilitating the transduction of environmental signals into gene expression. In this study, we applied molecular modeling methods to explore the hypothesis that unstructured inter-domain and subdomain linkers in bacterial TFs can function as sensors for carbohydrate signaling molecules. We combined molecular dynamics simulations and carbohydrate docking to analyze six repressors with GntR-type DNA-binding domains, including UxuR, GntR and FarR from Escherichia coli, as well as AraR, NagR and YydK from Bacillus subtilis. Protein models obtained from different time points of the dynamic simulations were subjected to sequential carbohydrate docking. We found that the inter-domain linker of the UxuR monomer binds D-fructuronate, D-galacturonate, D-glucose, and D-glucuronate with an affinity comparable to nonspecific interactions. However, these ligands formed multimolecular clusters, a feature absent in the UxuR dimer, suggesting that protein dimerization may depend on linker occupancy by cellular carbohydrates. D-glucose interacted with linkers connecting subdomains of the LacI/GalR-type E-domains in GntR and AraR, forming hydrogen bonds that connected distant structural modules of the proteins, while in NagR, FarR and YydK, it bridged the inter-domain linkers and a β-sheet within the HutC-type E-domains. Hence, our results establish flexible linkers as pivotal metabolic sensors that directly integrate nutritional cues to alter gene expression in bacteria. Full article

Mutations in TP53 inhibit p53 protective behaviors including cell cycle arrest, DNA damage repair protein recruitment, and apoptosis. The ubiquity of p53 in genome-stabilizing functions leads to an aberrant tumor microenvironment in TP53-mutated myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML). Profound immunosuppression mediated by myeloid-derived suppressor cells, the upregulation of cytokines and cell-surface receptors on leukemic cells, the suppression of native immune regulator cells, and metabolic aberrations in the bone marrow are features of the TP53-mutated AML/MDS marrow microenvironment. These localized changes in the bone marrow microenvironment (BMME) explain why traditional therapies for MDS/AML, including chemotherapeutics and hypomethylating agents, are not as effective in TP53-mutated myeloid neoplasms and demonstrate the dire need for new treatments in this patient population. The unique pathophysiology of TP53-mutated disease also provides new therapeutic approaches which are being studied, including intracellular targets (MDM2, p53), cell-surface protein biologics (immune checkpoint inhibitors, BiTE therapy, and antibody–drug conjugates), cell therapies (CAR-T, NK-cell), signal transduction pathways (Hedgehog, Wnt, NF-κB, CCRL2, and HIF-1α), and co-opted biologic pathways (cholesterol synthesis and glycolysis). In this review, we will discuss the pathophysiologic anomalies of the tumor microenvironment in TP53-mutant MDS/AML, the hypothesized mechanisms of chemoresistance it imparts, and how novel therapies are leveraging diverse therapeutic targets to address this critical area of need. Full article

The presence of aberrant double-stranded DNA (dsDNA) in the cytoplasm of cells is sensed by unique pattern recognition receptors (PRRs) to trigger innate immune response. The cyclic GMP–AMP synthase (cGAS)–stimulator of interferon genes (STING) signaling pathway is activated by the presence of non-self or mislocalized self-dsDNA from nucleus or mitochondria released in response to DNA damage or cellular stress in the cytoplasm. Activation of cGAS leads to the synthesis of the second messenger cyclic GMP–AMP (cGAMP), which binds and activates STING, triggering downstream signaling cascades that result in the production of type I interferons (IFNs) and proinflammatory cytokines. Here, we show that diverse immunostimulatory dsDNA ligands and chemotherapy agents like Doxorubicin and Taxol trigger the integrated stress response (ISR) by activating endoplasmic reticulum (ER) stress kinase, protein kinase RNA-like ER kinase (PERK), in addition to the canonical IFN pathways. PERK-mediated phosphorylation and inactivation of the alpha subunit of eukaryotic translation initiation factor-2 (eIF2α) result in the formation of stress granules (SGs). SG formation by dsDNA was significantly reduced in PERK knockout cells or by inhibiting PERK activity. Transcriptional induction of IFNβ and cytokines, ISR signaling, and SG formation by dsDNA was dampened in cells lacking PERK activity, STING, or key stress-granule nucleating protein, Ras-GAP SH3 domain-binding protein 1 (G3BP1), demonstrating an important role of the signal transduction pathway mediated by STING and SG assembly. Lastly, STING regulates reactive oxygen species (ROS) production in response to DNA damage, highlighting the crosstalk between DNA sensing and oxidative stress pathways. Together, our data identify STING–PERK–G3BP1 signaling axis that couples cytosolic DNA sensing to stress response pathways in maintaining cellular homeostasis. Full article

The mammary gland is a valuable model in cancer research and developmental biology. Gene delivery techniques are crucial for mammary tissue research to understand how genes function and study on diseases such as cancer. Viral vector-based approaches provide a high degree of transduction efficiency, but they raise safety and immunogenicity concerns, whereas non-viral vector-based approaches are considered safer and have lower immunogenicity than viral methods. Unfortunately, non-viral gene delivery has rarely been applied to the mammary glands because it is technically challenging. Here, we developed a novel method for in vivo transfection of epithelial cells lining murine mammary glands via intraductal injection of plasmid DNA using a breath-controlled glass capillary and subsequent electroporation (EP) of the injected area. Female mice were transfected with plasmids harboring the enhanced green fluorescent protein (EGFP) gene. Widespread EGFP fluorescence was observed in the mammary epithelial cells of the ducts and adipocytes adjacent to the ducts. As this in vivo gene delivery method is simple, safe, and efficient for gene transfer to the mammary glands, we named this technique “Mammary Intraductal Gene Electroporation” (MIGE). The MIGE method is a useful experimental tool for studies on mammary gland development and differentiation as well as breast cancer research. Full article

Soluble sugars are key determinants of fruit quality, directly influencing sensory attributes such as sweetness and flavor, as well as nutritional value and texture. Their content and composition are precisely regulated by sugar-metabolizing enzymes. Key enzymes, including invertase (INV), sucrose phosphate synthase (SPS), sucrose synthase (SUS), fructokinase (FRK), and hexokinase (HXK), play pivotal roles in these processes. However, a systematic and in-depth analysis of their regulatory mechanisms is currently lacking, which hinders a comprehensive understanding of the regulatory network governing fruit sugar metabolism. This review employs bibliometric analysis to systematically examine research trends in fruit sugar metabolism. Furthermore, it synthesizes recent advances in the coordinated regulatory mechanisms from the perspectives of transcriptional regulation, epigenetic modifications, and signal transduction, aiming to provide a clearer framework for future research. At the transcriptional level, transcription factor families such as MYB, WRKY, NAC, and MADS-box achieve precise regulation of sugar metabolism-related genes by specifically binding to the promoters of their target genes. Regarding epigenetic regulation, mechanisms including histone modifications, non-coding RNAs, and DNA methylation influence the expression of sugar-metabolizing enzymes at the post-transcriptional level by modulating chromatin accessibility or mRNA stability. Signaling pathways integrate hormonal signals (e.g., ABA, ethylene), environmental signals (e.g., temperature, light), and sugar-derived signals into the regulatory network, forming complex feedback mechanisms. These regulatory mechanisms not only directly affect sugar accumulation in fruits but also participate in fruit quality formation by modulating processes such as cell turgor pressure and carbon allocation. By integrating recent findings on transcriptional regulation, epigenetics, and signaling pathways, this review provides a theoretical foundation for fruit quality improvement and targeted breeding. Full article

Carbon dioxide (CO₂) is a key environmental factor that regulates the morphology of fruiting bodies in edible fungi. High CO₂ concentrations often lead to the formation of antler-shaped abnormal fruiting bodies in Ganoderma lucidum. Yet, the molecular response mechanisms underlying this process remain unclear. To address this gap, this study integrated transcriptomics and untargeted metabolomics to compare the transcriptional and metabolic profiles of G. lucidum fruiting bodies at three growth stages, cultivated under both normal (0.04%) and high CO₂ concentrations (0.3%). Metabolomic analysis revealed that, compared to the control groups, 387, 337, and 445 differentially accumulated metabolites were identified in the elevated-CO₂ groups, respectively. Moreover, high CO₂ concentrations led to a widespread down-regulation of various amino acids biosynthesis, accompanied by a marked accumulation of specific triterpenoids and steroids. This indicates distinct metabolite accumulation patterns in the fruiting bodies of G. lucidum cultivated under elevated CO₂. Furthermore, transcriptomic analysis showed that, at a key stage of fruiting body development, high CO₂ concentrations adversely affected gene expression of cell cycle-yeast, proteasome, DNA replication, mismatch repair, and meiosis-yeast pathways, which may decrease the cell division ability and prevent normal pileus development. Meanwhile, the differential expression of genes related to CO₂ signal perception and transduction and cell wall remodeling provided a molecular basis for the morphogenesis of the antler-type fruiting bodies. Overall, this study delineates a multi-layered, multi-pathway regulatory network through which high CO₂ concentrations affect the development and metabolism of G. lucidum, encompassing energy metabolism reprogramming, inhibition of cell division, and cell wall remodeling. This provides new insights into CO₂ as an environmental signal in fungal development and a theoretical basis for optimizing G. lucidum cultivation practices. Full article

DNA nanoparticles have emerged as potent platforms for wearable and implantable biosensors owing to their molecular programmability, biocompatibility, and structural precision. This study delineates two principal categories of DNA-based sensing materials, DNA hydrogels and DNA origami, and encapsulates their fabrication methodologies, sensing mechanisms, and applications at the device level. DNA hydrogels serve as pliable, aqueous signal transduction mediums exhibiting stimulus-responsive characteristics, facilitating applications such as sweat-based cytokine detection with limits of detection as low as pg·mL⁻¹ and microneedle-integrated hydrogels for femtomolar miRNA sensing. DNA origami offers nanometer-scale spatial precision that improves electrochemical, optical, and plasmonic biosensing, as shown by origami-facilitated luminous nucleic acid detection and ultrasensitive circulating tumor DNA assays with fM-level sensitivity. Emerging integration technologies, such as flexible electronics, microfluidics, and wireless readout, are examined, alongside prospective developments in AI-assisted DNA design and materials produced from synthetic biology. This study offers a thorough and practical viewpoint on the progression of DNA nanotechnology for next-generation wearable and implantable biosensing devices. Full article

The fungus Penicillium digitatum causes citrus green mold, a major postharvest disease. Understanding the molecular mechanisms underlying its development is crucial for devising effective control strategies. In this study, we performed a comprehensive transcriptomic analysis of P. digitatum across three key developmental stages: spores, germinated spores, and mycelia. A total of 2175 novel mRNAs, 3957 novel long non-coding RNAs (lncRNAs), and 144 circular RNAs (circRNAs) were identified in P. digitatum. Genetic variation analysis revealed 12,396 Insertion-Ddeletion and 23,264 single nucleotide polymorphisms, with their prevalence decreasing as development progressed. The expression levels, temporal expression patterns and significant differences in mRNAs and lncRNAs across different developmental stages were also observed. Functional enrichment analysis of differentially expressed mRNAs and differentially expressed lncRNA target genes highlighted key biological processes and pathways associated with macromolecular metabolism, signal transduction, DNA replication, and reactive oxygen species scavenging. Additionally, differential expression analysis explored the potential interactions between differentially expressed lncRNAs and their target genes, as well as those between lncRNAs and circRNAs. Our findings provide valuable insights into the complex regulatory networks underpinning the development and pathogenicity of P. digitatum, offering a foundation for future research aimed at controlling green mold. Full article

ATP hydrolysis drives essential processes across biology, from nucleic acid translocation and conformational switching to signal transduction. The GHKL ATPase family—DNA Gyrase B, Heat Shock Protein 90 (Hsp90), Histidine Kinases, and MutL homologs—shares a Bergerat-fold that couples nucleotide binding and hydrolysis to conformational changes, dimerization, and signaling. Despite their diverse roles, GHKL proteins rely on common ATP-dependent principles. Within this family, MutLα (MLH1-PMS2 in humans, Mlh1-Pms1 in yeast) is central to eukaryotic mismatch repair, where it provides the endonuclease activity needed for strand incision and coordinates interactions with other repair partners. MutLα exemplifies how the Bergerat-fold has been adapted to regulate DNA interactions, partner communication, and protein turnover on DNA. By examining MutLα through the lens of other GHKL proteins, we can clarify how ATP binding and hydrolysis drive its conformational dynamics, nuclease activation, and regulation within its pathway, highlighting how conserved mechanistic strategies are repurposed across biological systems. Full article

Nitrogen (N) is an essential nutrient for the growth and development of rice. However, excessive N fertiliser application and low N Use Efficiency (NUE) have led to serious environmental problems and threatened agricultural sustainability. In this study, we compared the physiological and transcriptomic profiles of roots of two cultivars exposed to normal nitrogen (NN) and low nitrogen (LN). The results showed that the LN treatment suppressed root growth and severely affected enzymatic activities in the roots of both rice cultivars compared to the NN treatment. Moreover, HJ753 exhibited significantly higher activities of NITRATE REDUCTASE (NR) and GLUTAMINE SYNTHETASE (GS) in its roots than DJ8 under both LN and NN conditions. Transcriptomic analysis identified 23,205 genes across all samples, with more than 5000 differentially expressed genes (DEGs) detected in response to LN stress in both cultivars. The KEGG analysis revealed that the DEGs were primarily involved in DNA replication, tryptophan metabolism, phenylpropanoid biosynthesis, plant hormone signal transduction, and N metabolism. Under LN stress, most genes associated with tryptophan metabolism and phenylpropanoid biosynthesis pathways remained stable or were upregulated in both cultivars. In contrast, genes related to auxin signalling transduction, N metabolism, and N utilisation exhibited significant genotype-specific expression patterns between HJ753 and DJ8. In conclusion, this study elucidated the genotypic differences in root development and N response mechanisms under LN stress at the molecular level, providing new insights into the regulatory mechanisms of N efficiency that may be used to develop and support the breeding of N-efficient rice cultivars. Full article

Background/Objectives: Selectively expressible RNA (seRNA) molecules represent a promising new platform for the induction of cell type-specific protein expression. Based on the sense–antisense interaction of the seRNA antisense domain with target cell-specific RNA molecules, the partial degradation of the seRNA molecule induces the activation of an internal ribosomal entry site to initiate translation. The selective expression of seRNA encoded proteins exclusively in target cells works both in vitro and in vivo but is associated with a lower expression intensity compared with classical mRNAs. Furthermore, seRNAs have so far been transfected into cells by plasmid-encoded seRNA expression systems, which is limiting their broad medical applicability. Here, we focus on the characterization of plasmid-based seRNA uptake and activation as well as on options to transfer the seRNA technology to additional vector systems to increase target cell-specific effector expression. Methods: seRNA constructs were generated as expression plasmids, AAV, DNA minicircles and IVT-RNA and delivered into different eukaryotic cell lines by transfection/transduction. Analyses were performed using fluorescence microscopy and, for quantitative analyses, flow cytometry. RNA stability and expression analyses were performed using qRT-PCR. Results: We show that seRNA-based plasmid systems are efficiently transfected into cells but that reduced RNA steady-state levels are present compared with control expression plasmids. This effect is most likely based on reduced transcription efficiency rather than seRNA stability. Furthermore, seRNA transcription from viral vectors or circular DNA significantly increased the effector expression of seRNAs and enabled linear expression regulation while maintaining target cell-specific activation and inactivation in non-target cells. Optimal results were achieved by adapting the technology to in vitro transcribed seRNA. Conclusions: Our data show that seRNA technology develops its full functionality regardless of the type of transfer vector used. Furthermore, expression strength can be regulated within a wide range while maintaining consistent functionality which will enable broad applicability in medicine in the future. Full article

(1) Background: After HBV infection, viral transcripts and host RNA form a multi-layered interwoven regulatory network. However, a comprehensive map encompassing mRNA, miRNA, lncRNA, and circRNA is still lacking. This absence complicates the systematic explanation of the molecular mechanisms driving immune escape and metabolic reprogramming during the persistent infection stage. (2) Methods: In this study, we established a mouse model of chronic HBV infection and analyzed the differential expression of mRNA, miRNA, lncRNA, and circRNA through whole transcriptome sequencing (WTS). We constructed a competing endogenous RNA (ceRNA) network to systematically evaluate the overall impact of HBV on the host’s immune-metabolic pathways. (3) Results: RNA sequencing results indicated that HBV infection significantly up-regulated 194 mRNAs, 18 miRNAs, 184 lncRNAs, and 28 circRNAs, while down-regulating 42, 16, 122, and 31 corresponding transcripts, respectively. The differentially expressed genes were primarily enriched in pathways related to metabolism, immunity/inflammation, and signal transduction-ligand receptor interactions. Furthermore, the competitive endogenous RNA networks of lncRNA-miRNA-mRNA and circRNA-miRNA-mRNA constructed on this basis further identified miR-185-3p as a key core node. (4) Conclusions: In this study, based on whole transcriptome data, the gene expression profiles of rcccDNA/Ad-infected Alb-Cre transgenic mice (chronic HBV infection model) and normal Alb-Cre mice were systematically compared, and the core regulatory factor miR-185-3p of key differentially expressed genes was screened. The microRNA is expected to provide a new target for the precise treatment of chronic hepatitis B by targeted intervention of viral replication and high liver inflammation. Full article

In agricultural production, plants commonly suppress their growth and development under abiotic stresses. We identified the heat shock transcription factor SlHsfC1, and overexpression (OE) lines resulted in a dwarf phenotype. Overexpression lines exhibited reduced cell size and elevated levels of bioactive gibberellins (GAs). However, applying external GA₃ did not restore the dwarf phenotype. Gene expression analysis showed that GA biosynthesis pathway genes (SlKO, SlKAO, SlGA20ox3, and SlGA20ox4) were upregulated, whereas GA metabolic pathway genes (SlGA2ox1 and SlGA2ox2) were downregulated, leading to the accumulation of bioactive gibberellins. However, GA signal transduction pathway genes (SlGAI2 and SlGAI3) were also upregulated, thereby impairing gibberellin signaling in these lines. Protein–DNA interaction assays confirmed that SlHsfC1 directly binds the SlGAI3 promoter and activates its expression. Thus, SlHsfC1 regulates plant height by modulating key genes in the gibberellin signaling pathway. Full article

To identify novel peptides with potential antiviral activities, a database search was performed based on the primary sequence of the peptide I24 (CLAFYACFC), the effective part of the antiviral peptide TAT-I24 consisting of peptide I24 and the cell penetrating TAT-peptide (amino-acids 48–60; GRKKRRQRRRPPQ). A Protein BLAST search identified several sequences with high similarity to I24 in diverse proteins, some of which are known to be involved in the interaction with nucleic acids. Selected sequences and newly designed variants of I24 were synthesized as TAT fusion peptides and tested for antiviral activity in two well-established models: baculovirus transduction of HEK293 cells and mouse cytomegalovirus (MCMV) infection of NIH/3T3 cells. Several of the TAT-fusion peptides exhibited antiviral activities with a potency comparable to TAT-I24. The ability of these peptides to bind double-stranded DNA suggested the same mode of action. Several peptides caused swelling of red blood cells (RBC) but with only one peptide clearly inducing haemolysis. With two exceptions, RBC swelling was observed with antivirally active peptides but not with less active peptides, indicating that antiviral activities are linked to an effect on membrane integrity of target cells. Structural prediction of the TAT-fusion peptides indicated formation of two α-helical elements, with several of these peptides showing remarkable similarity when subjected to structural alignment. Full article