Targeted deposition, spreading, and loss of histone H3K9 methylation over time. The black boxes indicate the location of the amplicons used for ChIP-qPCR (also compare with Figure 1B for a larger image of the VEGF-A gene promoter). The numbers above the bars indicate the distance of the qPCR amplicons from the zinc finger-binding site. (A) ChIP-qPCR measurements of H3K9me2 at the designated amplicons covering the promoter and gene body of VEGF-A. (B) ChIP-qPCR measurements of H3K9me3 at the designated amplicons covering the promoter and gene body of VEGF-A. The averages and SEM are based on two to three biological repeats. The corresponding P values can be found in Additional file 1: Table S2. VEGF-A, vascular endothelial growth factor A; bp, base pair; ZF-GLP-CD, zinc finger-protein lysine methyltransferase 1D-catalytic domain.