Figure 4From: A mechanistic role for the chromatin modulator, NAP1L1, in pancreatic neuroendocrine neoplasm proliferation and metastasesp57Kip2promoter methylation and NAP1L1 binding. Genomic DNA of normal BON cells and NAP1L1 silenced BON cells were treated with bisulfate, which converted cytosine of unmethylated p57Kip2 promoter into uracil. Methylation-specific polymerase chain reaction (MSPCR) was performed using two p57Kip2 promoter primers (forward first primer, CGCCAATCGCCGTGGTGTTG; forward second primer, ACTACATTATGCTAATCGCG; reverse primer, GCCAGGCCTGAGCGAGCGAG). Unmethylated p57Kip2 promoter resulted in low PCR products as demonstrated for NAP1L1-silenced cells (A) (*p < 0.05) indicating that NAP1L1 controls p57Kip2 expression by methylation of its promoter. In chromatin immunoprecipitation (ChIP) experiments, using the Pierce Agarose ChIP Kit (Thermo Scientific) according to the manufacturer’s instructions, a direct binding of NAP1L1 protein to the p57Kip2 promoter was evident in normal growing BON cells; non-proliferating cells did not silence the p57Kip2 promoter (B) (*p < 0.05). The calculated promoter expression in NAP1L1-bound DNA fragments is shown in relation to the control. Mean ± SEM.Back to article page