Fig. 1.

Elovl2 is a metabolic gene that serves as a marker of aging. (A) Correlation between DNA methylation of genes and aging. The significant sites are marked. (B) MeDip-qPCR and qPCR of Elovl2 in human fibroblasts. Error bars, SEM. **P < 0.01. Levels of significance were calculated with two-tailed Student’s t test. (C) DNA methylation level on the CpG island in intron 1 (CGI-I1) of Elovl2 in the brain and liver of 129/sv mice. Error bars, SEM. **P < 0.01. Levels of significance were calculated with two-tailed Student’s t test. (D) β-Galactosidase (β-GAL) staining on young (p5) human fibroblasts with or without H₂O₂ treatment. (Scale bar, 100 µm.) **P < 0.01. Levels of significance were calculated with two-tailed Student’s t test. (E) qPCR showing the transcriptional changes of cellular senescence markers in normal and H₂O₂-treated human fibroblasts. Error bars, SEM. *P < 0.05. Levels of significance were calculated with two-tailed Student’s t test. (F) MeDip-qPCR of Elovl2 in H₂O₂-treated human fibroblasts. Error bars, SEM. **P < 0.01. Levels of significance were calculated with two-tailed Student’s t test. (G) Coimmunoprecipitation on human fibroblasts with or without H₂O₂ treatment. (H) Western blotting showing that the H₂O₂-induced accumulation of DNMTs to the chromatins was CHD4 dependent. (I) The recruitment of CHD4 and 5-mC on DNA damage sites of cells irradiated with a 450-nm laser. (Scale bar, 5 µm.) For each group, 30 cells were treated.