Fig. 4.

YY1 sequences 201–226 are necessary and sufficient for recruitment of PcG proteins to DNA in vivo. (A Top) Schematic of the BGUZ reporter locus indicating the structural elements and the location of the PCR primers for ChIP experiments. (Middle and Bottom) Representative ChIP Southern blot from embryos expressing either the GALYY1Δ201–226, or the GAL 201–226 transgenes. Antibodies are shown above the lanes. Triangles indicate the increase in template concentration used for PCR (2 and 20 ng). (B) Quantitative ChIP data from three independent experiments with full-length GALYY1, GALΔ201–226, and GALYY1 201–226 transgenes. Values were normalized to the level of the GAL4 signal to normalize for equal amounts of GAL fusion protein bound to DNA in vivo. Error bars show the standard deviation from the mean. (C) YY1 recruits HDAC activity, but not H3K27 methyltransferase activity to the GAL-NP6-LacZ reporter. ChIP assays were performed with antibodies shown above the lanes. After PCR of either 2 or 20 ng DNA with primers specific for the GAL-NP6-LacZ reporter, samples were electrophoresed on agarose gels.