Spatiotemporal dynamics of protamine–DNA condensation revealed by high-speed atomic force microscopy

Nucleic Acids Research, Journal Year: 2025, Volume and Issue: 53(6)

Published: March 20, 2025

Abstract Protamines (PRMs) play a crucial role in sperm chromatin condensation, replacing histones to form nucleo–PRM structures, specifically PRM–DNA complexes. Despite their importance reproduction, the detailed mechanisms underlying PRM-mediated DNA condensation have remained elusive. In this study, we employed high-speed atomic force microscopy (HS-AFM) directly visualize real-time binding dynamics of PRM under physiological conditions. Our HS-AFM observations reveal that insertion initiating formation coils. Further, observed heterogeneous spatial distribution PRM-induced looping. With continuous addition, progresses through series folding transitions, forming coiled-like structures evolve into clockwise spirals, rod-shaped intermediates, and ultimately toroid-like nanostructures. Based on these observations, propose CARD (Coil-Assembly-Rod-Doughnut) model describe stepwise process toroid during condensation. findings underscore versatility capturing spatiotemporal interactions provide critical insights molecular driving compaction. This study advances our understanding architecture offers framework for future research organization, reproductive biology, nucleic acid therapeutics.

Language: Английский

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Nanoscopic Profiling of Small Extracellular Vesicles via High‐Speed Atomic Force Microscopy (HS‐AFM) Videography

Journal of Extracellular Vesicles, Journal Year: 2025, Volume and Issue: 14(4)

Published: March 26, 2025

Small extracellular vesicles (sEVs), which carry lipids, proteins and RNAs from their parent cells, serve as biomarkers for specific cell types biological states. These vesicles, including exosomes microvesicles, facilitate intercellular communication by transferring cellular components between cells. Current methods, such ultracentrifugation Tim-4 affinity method, yield high-purity sEVs. However, despite small size, purified sEVs remain heterogeneous due to varied intracellular origins. In this technical note, we used high-speed atomic force microscopy (HS-AFM) in conjunction with exosome markers (IgGCD63 IgGCD81) explore the origins of at single-sEV resolution. Our results first revealed nanotopology HEK293T-derived under physiological conditions. Larger (diameter > 100 nm) exhibited greater height fluctuations compared smaller ≤ nm). Next, found that mouse-origin IgGCD63, rabbit-origin IgGcontrol IgGCD81, iconic 'Y' conformation, similar structural dynamics properties. Last, marker antibodies predominantly co-localised sEVd nm but not nm, demonstrating CD63-CD81-enriched sEV CD63-CD81-depleted subpopulations. summary, demonstrate nanoscopic profiling surface on using HS-AFM is feasible characterising distinct subpopulations a mixture.

Language: Английский

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Strategies for the Viral Exploitation of Nuclear Pore Transport Pathways

Viruses, Journal Year: 2025, Volume and Issue: 17(2), P. 151 - 151

Published: Jan. 23, 2025

Viruses frequently exploit the host’s nucleocytoplasmic trafficking machinery to facilitate their replication and evade immune defenses. By encoding specialized proteins other components, they strategically target host nuclear transport receptors (NTRs) nucleoporins within spiderweb-like inner channel of pore complex (NPC), enabling efficient access nucleus. This review explores intricate mechanisms governing import export viral with a focus on interplay between factors determinants that are essential for these processes. Given pivotal role shuttling in life cycle, we also examine therapeutic strategies aimed at disrupting pathways. includes evaluating efficacy pharmacological inhibitors impairing assessing potential as antiviral treatments. Furthermore, emphasize need continued research develop targeted therapies leverage vulnerabilities trafficking. Emerging high-resolution techniques, such advanced imaging computational modeling, transforming our understanding dynamic interactions viruses NPC. These cutting-edge tools driving progress identifying novel opportunities uncovering deeper insights into pathogenesis. highlights importance advancements paving way innovative strategies.

Language: Английский

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Zooming into Gene Activation: Estrogen Receptor α Dimerization and DNA Binding Visualized by High-Speed Atomic Force Microscopy

ACS Nano, Journal Year: 2025, Volume and Issue: unknown

Published: April 18, 2025

Estrogen receptor α (ERα) is pivotal in gene regulation, particularly estrogen-responsive cancers. However, the full-length molecular dynamic structure of ERα remains elusive. In this study, we employ high-speed atomic force microscopy (HS-AFM) to visualize interactions with estrogen response element (ERE) under both ligand-present and ligand-absent conditions. binds ERE even absence estrogen, although presence ligand significantly enhances binding precision stability. Our real-time, high-resolution HS-AFM imaging captures structural transitions from monomeric dimeric forms, elucidating mechanisms by which modulates DNA-binding specificity. Based on these findings, propose a ligand-induced dimerization (LID) model, wherein facilitates optimal loading onto DNA. These insights deepen our understanding hormone signaling cancer hold promise for development future therapeutic strategies targeting hormone-related malignancies.

Language: Английский

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Nanoimaging of SARS-CoV-2 viral invasion toward the nucleus and genome

Cell Reports Physical Science, Journal Year: 2024, Volume and Issue: 5(9), P. 102111 - 102111

Published: July 24, 2024

The SARS-CoV-2 virus, responsible for the COVID-19 pandemic, has been linked to significant worldwide illness and death. Examining ultrastructure nanomechanical characteristics of viruses, from a physical standpoint, aids in categorizing their mechanical attributes, providing valuable information novel treatment approaches pinpointing susceptible regions that can guide precise medical interventions. This review presents structural virus particles, focusing on interaction with cells effects nuclear pore transit epigenetic modifications. We present latest progress utilizing high-speed atomic force microscope nanoscale observation its constituents. viruses utilize several components interact host's transport receptors nucleoporins complex influence genome modality. In this review, we also provide an updated summary how parts system these interactions change chromatin.

Language: Английский

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The SARS-CoV-2 ORF6 protein inhibits nuclear export of mRNA and spliceosomal U snRNA

PLoS ONE, Journal Year: 2024, Volume and Issue: 19(10), P. e0312098 - e0312098

Published: Oct. 31, 2024

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of disease 19 (COVID-19). SARS-CoV-2 infection suppresses host innate immunity and impairs cell viability. Among viral proteins, ORF6 exhibits potent interferon (IFN) antagonistic activity cellular toxicity. It also interacts with RNA export factor RAE1, which bridges nuclear pore complex receptors, suggesting an effect on export. Using Xenopus oocyte microinjection system, I found that blocked not only mRNA but spliceosomal U snRNA. further demonstrated affects interaction between RAE1 receptors inhibits binding RAE1. These effects may cumulatively block several classes RNA. binds forms oligomers. findings provide insights into suppression immune responses reduction in viability caused by infection, contributing to development antiviral drugs targeting ORF6.

Language: Английский

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Effect of C- and N-Terminal Polyhistidine Tags on Aggregation of Influenza A Virus Nuclear Export Protein

Biochemistry (Moscow), Journal Year: 2024, Volume and Issue: 89(12-13), P. 2238 - 2251

Published: Dec. 1, 2024

Language: Английский

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