Micronucleus Assay Applications in Genotoxicity Assessment

The micronucleus assay is a well established cytogenetic technique for detecting chromosomal damage and genome instability in cells exposed to physical, chemical or biological stressors. Micronuclei arise when whole chromosomes or acentric fragments fail to incorporate into daughter nuclei during mitosis, forming small extranuclear bodies. This assay may be performed in vivo, ex vivo or in vitro and is widely used in regulatory genotoxicity testing, environmental biomonitoring and mechanistic studies of DNA damage. Variants such as the cytokinesis-block micronucleus (CBMN) assay enable specific scoring of binucleated cells to improve sensitivity and reduce confounding by cell cycle effects. Recent advances in automated microscopy, imaging flow cytometry and deep-learning image analysis have increased throughput and objectivity, while multiplex biomarker approaches permit concurrent assessment of DNA repair foci and cell cycle stages. Applications range from occupational exposure monitoring to safety assessment of novel materials, pharmaceuticals and dietary interventions. The assay’s global significance lies in its simplicity, adaptability and quantitative output, informing risk assessment and protective strategies across diverse fields.

Research from Nature Portfolio

Recent studies have evaluated genomic instability in professionals chronically exposed to low-dose ionising radiation. Analysis of peripheral blood lymphocytes revealed a significant elevation in micronucleus frequency and various chromosomal aberrations among interventional radiologists compared with matched controls. Although markers of DNA repair focus formation remained unchanged, increased amplification of specific gene segments was observed, indicating ongoing genome rearrangement. These findings underscore the micronucleus assay’s utility for biodosimetry and long-term monitoring of radiation-associated genotoxic risk.

Micronucleus Assay Applications in Genotoxicity Assessment publication trend

The graph below shows the total number of articles in micronucleus assay applications in genotoxicity assessment across all publications each year (not limited to Nature Index journals).

Technical terms

Micronucleus: A small extranuclear structure containing whole chromosomes or fragments excluded from the primary nucleus during cell division.

Clastogenic: Causing structural chromosome breaks that can lead to fragment-derived micronuclei.

Aneugenic: Disrupting the mitotic spindle or centromere function, resulting in whole-chromosome loss into micronuclei.

Cytokinesis-block micronucleus (CBMN) assay: A variant employing cytochalasin B to arrest cytokinesis, enabling scoring of binucleated cells for accurate micronucleus detection.

Imaging flow cytometry: A high-throughput technique combining microscopy and flow cytometry to capture morphological images and quantitative data from thousands of cells per minute.

γH2AX: A phosphorylated histone variant that marks sites of DNA double-strand breaks and is used as an adjunct biomarker in multiplex assays.

References

1. A multi-biomarker micronucleus assay using imaging flow cytometry. Archives of Toxicology (2024).
2. In vitro micronucleus assay: Method for assessment of nanomaterials using cytochalasin B. Frontiers in Toxicology (2023).
3. Effects of low-dose ionizing radiation on genomic instability in interventional radiology workers. Scientific Reports (2023).
4. Micronucleus Assay: The State of Art, and Future Directions. International Journal of Molecular Sciences (2020).
5. Cytokinesis-Block Micronucleus Cytome Assay Evolution into a More Comprehensive Method to Measure Chromosomal Instability. Genes (2020).
6. The in vitro micronucleus assay using imaging flow cytometry and deep learning. npj Systems Biology and Applications (2021).