Involvement of C/EBPα isoforms in PRC2-mediated H3K27me3 and CTNNA1 expression from the retained allele. (A) ChIP analyses were performed with the indicated antibodies in the HL-60, NB4, and KG-1 leukemia cell lines. Note that the C/EBPα (N) antibody recognizes only the p42 wild-type full-length C/EBPα protein, whereas C/EBPα (C1) and C/EBPα (C2) recognize both p42 and p30 C/EBPα. (B) Western blot analysis of p42, p30 C/EBPα, and α-catenin proteins in HL-60, NB4, and KG-1 leukemia cells. Note that the ratio of p42/p30 is significantly reduced only in HL-60 cells. (C) HL-60, NB4, and KG-1 cells were treated with 10nM rapamycin for 96 hours followed by Western blot analyses with the indicated antibodies. (D) ChIP analyses were performed with the indicated antibodies in HL-60, NB4, and KG-1 cells treated with 10nM rapamycin for 96 hours. (E-H) Effects of p42 and p30 C/EBPα overexpression on CTNNA1 levels. Retrovirally mediated overexpression of p42 and p30 C/EBPα (E) in HL-60 cells as determined by Western blot analysis (F). The levels of CTNNA1 transcripts and α-catenin protein were determined by real-time quantitative RT-PCR (G) and Western blot analysis (H), respectively.