C/EBPϵ, Rb, and E2F1 can be found in complexes together in 32Dcl3 cells. (A) Protein lysates were made from 32Dcl3 parental cells (32D) and 32Dcl3 cells stably transfected with a constitutively expressed C/EBPϵ gene (32Dϵ). Lysates were immunoprecipitated with either E2F1 or Rb antibodies followed by Western analysis with a C/EBPϵ antibody. (B) Protein lysates from 32Dcl3 cells untreated (day 0) or treated with G-CSF (day 4) were immunoprecipitated with either E2F1 or Rb antibodies followed by Western analysis with a C/EBPϵ antibody. The blots (A, B) were stripped and rehybridized with E2F1 and Rb antibodies.