Fig 1: ID2 inhibits E2A-mediated transcriptional activation of p21 expression. (A) Venn diagram was drawn to identify the possible interacted genes of ID2. (B) The Common genes derived from Venn were used to perform KEGG enrichment analysis. (C, D) Endogenous interaction between ID2 and E2A was detected in A549 and H460 cells. (E) The interaction domain between ID2 and E2A was identified by WB analysis. (F, G) p21 expression was detected following E2A OE in A549 and H460 cells. (H) Relative luciferase activity of CDKN1A promoter region in A549 (left) and H460 (right) cells. (I) Evolutionarily conserved E-box binding sites. (J) The predicted E2A binding site in the CDKN1A locus. (K) ChIP assay was used to illustrate the transcriptional regulation of CDKN1A. **P < 0.01; ***P < 0.001.