Reduced binding of CP2 and RNA polymerase II to the SSE in K562 cells overexpressing p14 NF-E4 demonstrated by ChIP. Chromatin from K562 cells transduced with either the MSCV (▪) or MSCV p14 NF-E4-HA (, □) retrovirus was immunoprecipitated using antisera to CP2, NF-E4, HA, TBP, RNA polII, and p45 NF-E2 as indicated. Preimmune sera served as the control (PI). Quantitative PCR was performed with primer pairs to amplify the SSE in the γ-promoter SSE (▪, ) or the MYOD gene (□).