Fig. 4

Kaiso inhibits Dll-1 expression in intestinal cells. a, b Dll-1, but not Dll-4, is reduced in intestinal tissues from Kaiso ^Tg mice compared to NonTg as revealed by qRT-PCR (a) and IHC (b). c Dll-1 protein levels are reduced in intestinal epithelial cells from Kaiso ^Tg relative to NonTg. d and e Stable Kaiso-depleted (shKaiso) SW480, HCT116 and HT29 colon cells express increased Dll-1 transcripts (d) and protein (e) compared to controls as determined by qRT-PCR (normalized to β-actin) and western blot analyses, respectively. Western blots were quantified by densitometry (as relative fold change over control). f Schematic representation of the human DLL1 promoter spanning −1000 to +400 bp of the transcription start site (+1). Arrowheads denote regions amplified by PCR; vertical lines – CpG dinucleotides; CGI – CpG island. g Kaiso associates with the DLL1 KBS in HCT116 and HT29 cells, but not SW480 cells. De-methylation with 5’aza-cytidine (5’aza) abolishes Kaiso binding; Histone H3 (H3) and IgG serve as positive and negative controls, respectively. Asterisk (*) denotes primer dimers. Statistical significance was determined by student’s t-test. Error bars are SEM, ns – not significant, **p < 0.005. Scale bar, 50 μm