Foci Counter

Green foci showing DNA damaged sites where repair-proteins co-localise

Confocal image showing HepG2 nuclei (blue) with green and red foci peppered within

Red foci showing DNA damaged sites where other repair-proteins co-localise

In the realm of cellular analysis, foci quantification stands out as a critical process, shedding light on the intricate details of cellular responses, particularly in the context of DNA damage and repair. Foci, localized concentrations of proteins or other molecular markers, serve as indicators of specific cellular events, with DNA double strand breaks being a prominent example. Such breaks could be initiated via irradiation from the singletron accelerator in CIBA and studied in a controlled manner, providing valuable insights to the damage and repair mechanisms of cells.

The process of foci quantification involves the systematic counting and analysis of these concentrated points within a cell or nucleus. This quantification is often carried out using advanced imaging techniques, such as high resolution laser scanning 3D confocal microscopy, where specific markers or dyes highlight the foci for precise identification and analysis.

In the context of DNA double strand break analysis, foci quantification becomes especially crucial. Automated methods, often integrated with image processing algorithms, enable the efficient and accurate identification of these foci, providing us with quantitative data on the extent of DNA damage. Parameters such as foci counts, volumetric properties, and intensity variations are meticulously assessed, offering a comprehensive view of the cellular response to various stimuli, such as radiation or genotoxic stress.

References

[1]R. J. Tuieng. Investigating DNA damage induction by photons and protons in vitro using 3D confocal imaging and automatic volumetric analysis, Undergraduate thesis, National University of Singapore. 2020
[2]Mi, Z., Chen, CB., Tan, H.Q. et al. Quantifying nanodiamonds biodistribution in whole cells with correlative iono-nanoscopy. Nat Commun 12, 4657 (2021). https://doi.org/10.1038/s41467-021-25004-9
[3]

T. Y. Chua. Automated 3-dimensional quantification and analysis of DNA damage foci., Master’s thesis, National University of Singapore. 2024.

Content by Chua Tze Yen and Dr. Chen Ce-Belle, 2024