Assembly of the multiprotein repressor complex is dependent on PRMT5 enzymatic activity. (A) ChIP analysis on chromatin derived from PRMT5Δ-f– expressing K562 cells with the stated Abs. The precipitated DNA was amplified with primers specific for the γ-promoters. Enrichment was calculated relative to normal rabbit IgG. The error bars correspond to the SD. Each experiment was performed 3 times independently. Binding of CK2α, SUV4-20h1 and DNMT3A were not significant (P > .05) using Fisher exact test. (B) Western blot analysis of proteins immunoprecipitated from PRMT5Δ-f–expressing K562 cells with anti-FLAG Ab. A mock IP with normal rabbit IgG was used as a negative control. Abs used are indicated on the right.