Gamma H2ax Foci
Gamma H2ax Foci - Related Videos
04:09
Assessing DNA Damage Foci: To Identify Radiation-Induced DNA Damage Foci in Cancer Cell Line Using Immunofluorescence Staining
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2023
This video describes a protocol to detect radiation-induced DNA repair foci in the colon cancer cell lines using immunofluorescence staining. DNA repair proteins get activated at the DNA damage site; therefore, we can detect them using specific antibodies and visualize them under a fluorescence microscope.
08:48
Quantitation of γH2AX Foci in Tissue Samples
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Cited by 7 •
2010
Quantitation of DNA double-strand breaks on the basis of γH2AX foci has become an invaluable tool, particularly in radiation biology, for the evaluation of tissue radiosensitivity and effects of radiation modifying compounds. Here we demonstrate the use of an immunofluorescence assay for quantitation of γH2AX foci in tissue samples.
06:53
Quantification of γH2AX Foci in Response to Ionising Radiation
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Cited by 23 •
2010
Quantification of DNA double-strand streaks using γH2AX formation as a molecular marker has become an invaluable tool in radiation biology. Here we demonstrate the use of an immunofluorescence assay for quantification of γH2AX foci after exposure of cells to radiation.
08:23
An Automated Microscopic Scoring Method for the γ-H2AX Foci Assay in Human Peripheral Blood Lymphocytes
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Cited by 7 •
2021
This protocol presents the slide preparation and automated scoring of the γ-H2AX foci assay on peripheral blood lymphocytes. To illustrate the method and sensitivity of the assay, isolated lymphocytes were irradiated in vitro. This automated method of DNA DSB detection is useful for fast and high-throughput biological dosimetry applications.
09:33
Methods to Classify Cytoplasmic Foci as Mammalian Stress Granules
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Cited by 33 •
2017
Stress Granules (SGs) are nonmembranous cytoplasmic structures that form in cells exposed to a variety of stresses. SGs contain mRNAs, RNA-binding proteins, small ribosomal subunits, translation-related factors, and various cell signaling proteins. This protocol describes a workflow that uses several experimental approaches to detect, characterize, and quantify bona fide SGs.
FAQs
DNA double-strand breaks activate kinases including ATM, ATR, and DNA-PK, which phosphorylate H2AX at serine 139. This modification produces γ-H2AX across chromatin surrounding the lesion rather than only at the precise break point. The resulting signal expands the detectable damage region and helps organize the cellular response to genomic injury.
Phosphorylation spreads across chromatin near a double-strand break, creating a broader γ-H2AX domain. This distribution provides a platform that recruits and organizes DNA repair proteins around the damaged region. As a result, γ-H2AX foci indicate not only the presence of a break but also the surrounding chromatin environment involved in the repair response.
The number of foci provides an indication of the cellular burden of DNA damage, while their persistence offers information about how long damage-associated signals remain detectable. Measuring both features helps researchers monitor repair kinetics and compare cellular responses to different genotoxic stresses. Elevated or sustained signals can therefore provide insight into genome stability and repair behavior.
ATM, ATR, and DNA-PK are kinases identified as contributors to H2AX phosphorylation at serine 139 after DNA damage. Their activity generates the γ-H2AX signal that marks chromatin surrounding double-strand breaks. Considering these kinases is important when interpreting foci formation because the signal reflects an enzymatic damage-response process, not merely the physical presence of broken DNA.
Researchers commonly detect γ-H2AX foci with immunofluorescence microscopy. This approach makes phosphorylated H2AX clusters visible within cells, allowing investigators to quantify their abundance and examine how the signal changes over time. The resulting measurements can be used to follow DNA damage and repair kinetics after exposure to ionizing radiation, chemotherapy, or other genotoxic stresses.
These foci are useful for assessing genomic damage and repair responses in studies of ionizing radiation, chemotherapy, and other genotoxic stresses. Researchers can use changes in foci abundance or persistence to evaluate cellular responses and investigate genome stability. The measurements also support research into disease mechanisms and the effects of potential therapeutic agents.