Effect of FOG-1 mutants lacking NuRD or CtBP binding on β-chain promoter. (A) Structure of FOG-1 mutants: ΔN-FOG-1, lacking NuRD-binding N-terminus²⁷ ; ΔCtBP-FOG-1, with replacement of 2 amino acids essential for CtBP binding²⁸ ; ΔN/ΔCtBP-FOG-1, carrying both mutations of ΔN and ΔCtBP. (B) Coexpression analysis using FOG-1 mutants. PT18 cells were transfected with 5 μg of reporter plasmid β-69/pGL3-Basic with or without 3 or 10 μg of pCR-3.1 (mock), pCR-FOG-1 (wild-type), pCR-ΔN-FOG-1 (ΔN), pCR-ΔCtBP-FOG-1 (ΔCtBP), or pCR-ΔN/ΔCtBP-FOG-1 (ΔN/ΔCtBP). The ratio of each luciferase activity to that without coexpression plasmid was represented as relative luciferase activity. Data represent the average ± SD of triplicate samples.