The effect of KDM4B on histone methylation of N-Myc target genes. A) Chromatin immunoprecipitation and real-time polyermase chain reaction (PCR) assess the binding of N-Myc, KDM4B, RNA polymerase II (Pol ll), H3K9me3/me2 on miR17HG, CDC25A, TRIP13, and SDC1 genes in SK-N-BE2 cells. BS = binding site; NS= nonspecific sites. B) Chromatin immunoprecipitation–PCR assessment of binding of N-Myc, KDM4B, and H3K9me3 on miR17HG and CDC25A after 24-hour N-Myc induction with 1 µg/mL of doxycycline in MYCN3 cells. The N-Myc and KDM4B enrichment represents percentage of input while the H3K9me3 enrichment represents percentage of histone H3.