(Q) BRCA1 reporter assay in KLF4-/- MEFs, KLF4-/- MEF with transfection of wild-type (KLF4WT) or mutant KLF4 (KLF4YYR/AAA, KLF4C403A and KLF4ΔZinc2). The depleted the zinc domain or mutated zinc finger (KLF4C403A and KLF4ΔZinc2) on KLF4 impairs the KLF4-driven BRCA1 expression, while no effect was observed between wild-type and KLF4YYR/AAA mutant. n=3, p values were labeled in figure, one-way ANOVA assay. 