DNA, Volume 5, Issue 4 (December 2025) – 3 articles

Multiple sclerosis (MS) is a chronic autoimmune neurodegenerative disorder characterized by progressive demyelination and axonal degeneration within the central nervous system, driven by complex genomic and epigenomic dysregulation. Its pathogenesis involves aberrant DNA methylation patterns at CpG islands of numbers of genes like OLIG1 and OLIG2 disrupting protein expression at myelin with compromised oligodendrocyte differentiation. Furthermore, histone modifications, particularly H3K4me3 and H3K27ac, alter the promoter regions of genes responsible for myelination, affecting myelin synthesis. MS exhibits chromosomal instability and copy number variations in immune-regulatory gene loci, contributing to the elevated expression of genes for pro-inflammatory cytokines (TNF-α, IL-6) and reductions in anti-inflammatory molecules (IL-10, TGF-β1). Vitamin D deficiency correlates with compromised immune regulation through hypermethylation and reduced chromatin accessibility of vitamin D receptor (VDR) dysfunction and is reported to be associated with dopaminergic neuronal loss. Vitamin D supplementation demonstrates therapeutic potential through binding with VDR, which facilitates nuclear translocation and subsequent transcriptional activation of target genes via vitamin D response elements (VDREs), resulting in suppression of NF-κB signalling, enhancement of regulatory T-cell (T_reg) responses due to upregulation of specific genes like FOXP3, downregulation of pro-inflammatory pathways, and potential restoration of the chromatin accessibility of oligodendrocyte-specific gene promoters, which normalizes oligodendrocyte activity. Identification of differentially methylated regions (DMRs) and differentially expressed genes (DEGs) that are in proximity to VDR-mediated gene regulation supports vitamin D supplementation as a promising, economically viable, and sustainable therapeutic strategy for MS. This systematic review integrates clinical evidence and eventual bioinformatical meta-analyses that reference transcriptome and methylome profiling and identify prospective molecular targets that represent potential genetic and epigenetic biomarkers for personalized therapeutic intervention. Full article

Plants have evolved a complex, multilayered immune system that integrates molecular recognition, signaling pathways, epigenetic regulation, and small RNA-mediated control. Recent studies have shown that DNA-level regulatory mechanisms, such as RNA-directed DNA methylation (RdDM), histone modifications, and chromatin remodeling, are critical for modulating immune gene expression, allowing for rapid and accurate pathogen-defense responses. The epigenetic landscape not only maintains immunological homeostasis but also promotes stress-responsive transcription via stable chromatin modifications. These changes contribute to immunological priming, a process in which earlier exposure to pathogens or abiotic stress causes a heightened state of preparedness for future encounters. Small RNAs, including siRNAs, miRNAs, and phasiRNAs, are essential for gene silencing before and after transcription, fine-tuning immune responses, and inhibiting negative regulators. These RNA molecules interact closely with chromatin features, influencing histone acetylation/methylation (e.g., H3K4me3, H3K27me3) and guiding DNA methylation patterns. Epigenetically encoded immune memory can be stable across multiple generations, resulting in the transgenerational inheritance of stress resilience. Such memory effects have been observed in rice, tomato, maize, and Arabidopsis. This review summarizes new findings on short RNA biology, chromatin-level immunological control, and epigenetic memory in plant defense. Emerging technologies, such as ATAC-seq (Assay for Transposase-Accessible Chromatin using Sequencing), ChIP-seq (Chromatin Immunoprecipitation followed by Sequencing), bisulfite sequencing, and CRISPR/dCas9-based epigenome editing, are helping researchers comprehend these pathways. These developments hold an opportunity for establishing epigenetic breeding strategies that target the production of non-GMO, stress-resistant crops for sustainable agriculture. Full article

Background/Objectives: Intrinsically disordered protein regions (IDRs) are difficult to study due to their flexible nature and transient interactions. Computational folding using AlphaFold may offer one way to explore potential folding of these regions under various conditions. Human DNA topoisomerase IIα (TOP2A) is an essential enzyme involved in regulating DNA topology during replication and cell division. TOP2A has an IDR at the C-terminal domain (CTD) that has been shown to be important for regulating TOP2A function, but little is known about potential conformations that it may undertake. Methods: Utilizing the AlphaFold 3 (AF3) model by way of AlphaFold Server, TOP2A was folded as a dimer first without and then with 29 literature-supported post-translational modifications (PTMs) and DNA to observe whether there is predicted folding. Results: TOP2A CTD does not fold in the absence of PTMs. With the addition of PTMs, however, the CTD is predicted to fold into a globular bundle of loops and α-helices. While DNA alone did not induce folding, in the presence of PTMs, DNA ligands increased helicity of the folded CTD and caused it to interact at different core domain interfaces. In addition, DNA is predicted to enable folding of the TOP2A CTD in the presence of fewer PTMs when compared to the absence of DNA. Conclusions: AF3 predicts the folding of TOP2A CTD in the presence of specific PTMs, and this folding appears to shift to allow binding to DNA in functionally relevant regions. These studies provide predicted folding patterns that can be tested by biochemical approaches. AF3 may support the development of testable hypotheses regarding IDRs and enables researchers to model protein-DNA interactions. Full article