Figure 3.

Quantitation of telomere length by fluorescence in situ hybridization. Spleen cells from M. spretus, BALB/c, or (BALB/c × M. spretus)F1 mice were stimulated in vitro. Metaphase preparations derived from these activated cells were analyzed by quantitative fluorescence hybridization with a Cy3-labeled telomere-specific peptide nucleic acid probe (16, 17). Telomere fluorescence intensity was calculated from digital images by using dedicated software and is expressed in telomere fluorescence units with each unit corresponding to 1 kb of hybridized T2AG3 in plasmid DNA (16) by in situ hybridization with a fluorescein isothiocyanate-conjugated telomere-specific peptide–nucleic acid probe, and telomere length was calculated by scanning and quantitation of fluorescence signal.