A tethered p45/MafG heterodimer rescues α- and β-globin expression in the CB3 cell line. (A) Gel-shift assays were performed using nuclear extracts from MEL cells, untransfected CB3 cells, and CB3 cells stably transfected with either expression vector (EF1αneo) alone, or expression vector coding for a tethered p45/MafG heterodimer (see notations at top of lanes). An NF-E2 DNA-binding site derived from the human PBGD deaminase promoter was used as a probe. The arrow indicates the bound complex. The complex formed from p45/MafG tethered heterodimer migrates slightly slower than NF-E2 in MEL cells, presumably because of the mass of the linker segment. Not all clones transfected with the construct coding for p45/MafG express the heterodimer. (B) RNase protection analysis of cell lines described above. Probes were specific for mouse α- and βmajor-globin transcripts. γ-Actin was used as an internal control.
