ChIP analysis of C/EBPα and C/EBPε in the leukemic NB4 cell line.

(A) Chromatin immunoprecipitations were performed from uninduced (0) and ATRA-induced (48 h) NB4 cells using antibodies specific for C/EBPε (lanes 2-3) and C/EBPα (lanes 4-5), a no-antibody control (−) (lanes 1,9), and preimmune serum (PIS) controls (lanes 6-7). The precipitated chromatin was analyzed using primers specific for the human LF (LF) promoter (top panel) and the HNP promoter (bottom panel). Input HNP chromatin (1:10 dilution) is represented in lane 8. This experiment was repeated 3 times. The identities of PCR products obtained were confirmed by dideoxy sequencing. (B) Western blot analysis of whole cell extracts prepared from uninduced (0) and ATRA-induced (48 h) NB4 cells was performed and probed with C/EBPα and C/EBPε antibodies. The molecular weights of the proteins detected are shown in kilodaltons.