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Updated: Jul 18, 2026
Immunofluorescence Microscopy of γH2AX and 53BP1 for Analyzing the Formation and Repair of DNA Double-strand Breaks
Published on: November 3, 2017
[A distinct whole nucleus stain pattern of gamma H2AX induced by N-methyl-No-nitro-N-nitrosoguanidine]
Yan-ke Yu1, Zheng-wei Dong, Wei Shi
1Department of Public Health, Center for Environmental Genomics, College of Medicine, Zhejiang University, Hangzhou 310058, China.
Objective:
To characterize the DNA damage property represented by the distinct whole nucleus stain pattern of gammaH2AX induced by N-methyl-No-nitro-N-nitrosoguanidine (MNNG).
Methods:
MNNG-induced gammaH2AX foci formation in human amnion FL cells was observed by immunofluorescent microscopy. DNA double-stranded breaks (DSBs) were detected by neutral comet assay. General DNA damages were detected by alkaline comet assay.
Result:
A distinct whole nucleus stain pattern of gammaH2AX was induced by high concentration MNNG (10 mg/L). 1 mg/L MNNG also induced this type of stain pattern in a small fraction of cells, although the effect was transient. Neutral comet assay did not detect any significant DSBs formation in this type of cells, while alkaline comet assay revealed the presence of DNA damage.
Conclusion:
Although normal gammaH2AX foci were regarded as a biomarker for DSBs, the whole nucleus stain pattern might represent DNA damage other than DSBs.
