Fig. 2. Identities of the C1–C3 complexes. (A) EMSA was performed with nuclear extracts from NIH-3T3 cells transfected with the indicated constructs. ‘C’ stands for extracts transfected with an empty vector, pcDNA3. The positions of the indicated homo- and heterodimers of LAP and LIP are labeled on the left, while C1–C3 complexes in Ba/F3 cells are marked on the right. Supershifted complexes with antibodies against C/EBPβ are indicated by an open arrow. Nuclear extracts used in lanes 4 and 5 were analyzed using a western blot with antibodies against the C-terminus of C/EBPβ. The doublets represent the 29 and 31 kDa LAP. (B) ChIP assays with antibodies against C/EBPβ and a negative control, Skp2. A fragment containing all three C/EBP-binding sites was amplified. (C) Transient co-transfection assay of Ba/F3 cells with the indicated constructs; normalized luciferase activities are shown relative to that of PBE-luc.