Figure 4  ChIP Assay
MEL cells (A) and 15.5-dpc fetal liver cells (B) were treated as detailed in Materials and Methods. 10% of the sample was saved as total input (Inp); remaining samples were divided: plus Sox6 antibody (Ab+), minus Sox6 antibody (Ab−), as well as no DNA (DNA−) and normal rabbit IgG (IgG) that served as negative controls. Other controls for these experiments included PCR within the promoter of the α-globin gene and intron 24 of the p gene. Both were negative (unpublished data). PCR was carried out using primer pairs flanking the Sox/Sox6 binding sites (see Material and Methods) of the ɛy proximal promoter. For all reactions, we used 2 μl of immuno-precipitated DNA and 2 μl of 1/100 total input. Semiquantitative PCR was done within the exponential range. Multiple independent experiments were done.