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Updated: Oct 9, 2026

Telomere Length and Telomerase Activity; A Yin and Yang of Cell Senescence
Published on: May 22, 2013
Validation and development of quantitative flow cytometry-based fluorescence in situ hybridization for intercenter
1Department of Paediatrics, Faculty of Medicine, The University of Hong Kong, Queen Mary Hospital, Pokfulam, Hong Kong.
Background:
Telomeres are highly conserved repeats at the ends of chromosomes that maintain chromosome stability and reflect the replicative potential of cells. Telomere length can be determined by Southern blot hybridization or quantitative fluorescence in situ hybridization (Q-FISH). Recently, two flow cytometry-based (Flow) FISH protocols have been published.
Methods:
We compared the telomere length measured by Southern blotting and Flow FISH using standard beads to calibrate and quantify the fluorescence intensity.
Results:
The telomeric fluorescence of cord blood and peripheral blood mononuclear cells was similar to that reported by other studies. There was a linear relationship between the telomeric fluorescence determined by Flow FISH and the telomere fragment size determined by Southern blotting (r = 0.89; P < 0.001).
Conclusion:
It is important to set up a center-specific curve and select appropriate cell lines for reference. This Q-Flow FISH protocol will facilitate the measurement of telomere length and allow more meaningful comparison of data (in standard fluorescence units or fragment size) between institutes.

