FIGURE 4.

Shortening of telomeres and increases in p15, p16, and p21 genes in telomerase-deficient lungs. A, quantitative FISH experiment result for isolated AECII from G3 TERC-null mice. The telomere length is represented by fluorescence intensity in scatter plot style. B and C, the mRNA levels of p15 (B) and p21 (C) were determined by quantitative real-time PCR from three WT or G3 TERC-null animals as indicated. D–F, the mRNA levels of p15 (D), p16 (E), and p21 (F) were determined by quantitative real-time PCR from three WT or G3 TERT-null animals as indicated. G, P16 and SPC expression by immunostaining on pulmonary sections from G3 TERT-null mice. The left panels are representative micrographs, and the right bar graph shows the quantitative data (mean ± S.D. (error bars)) of three experiments. H, HP1γ and SPC staining on pulmonary sections from G3 TERT-null mice using specific antibodies. The left panels are representative micrographs, and the right bar graph shows the quantitative data (mean ± S.D.) of three experiments.