(A) KLF4+/+, KLF4-/- MEFs, KLF4-/- MEF with wild-type KLF4 or KLF4-Zinc 2-YYR/AAA mutant were treated with 5-10 µM cisplatin for 48 hours followed by measuring the expression of PARP1, p21 and Bax. Loss of PARylation on KLF4 impairs KLF4-mediated inhibition of apoptosis in the presence of genotoxic stress. 