The bona fide DNA-binding domain of Sp2 is dispensable for genomic binding.

Sp2ko MEFs re-expressing Flag-tagged full-length Sp2 (Flag-Sp2FL), the N-terminal domain (Flag-Sp2NT) or the C-terminal zinc finger domains (Flag-Sp2ZF) were subjected to ChIP-seq analysis. (A) Venn diagram showing the overlap of sites bound by Flag-Sp2FL, Flag-Sp2NT and Flag-Sp2ZF with sites bound by endogenous Sp2 in wild type MEFs. (B) Full-length Sp2 and the N-terminal region of Sp2 have similar chromatin binding efficiencies. ChIP-seq tag counts (normalized to 20x10⁶ reads) at individual Flag-Sp2NT and Flag-Sp2FL peaks found in both samples were plotted against each other. (C) Sites bound by Flag-Sp2NT represent high affinity binding sites of native Sp2. Individual native Sp2 peaks [18] were plotted against their normalized tag counts. Those sites that were also detected by ChIP-seq in Sp2ko MEFs expressing the N-terminal domain of Sp2 (Flag-Sp2NT mutant) were overlaid with red dots. (D) Representative binding profiles of Sp2 in wild type MEFs (Sp2 / wt), and of Flag-Sp2FL, Flag-Sp2NT and Flag-Sp2ZF expressed in Sp2ko MEFs. (E) Schematic representation of the genomic binding features of Sp1/Sp3 and Sp2 based on the results shown in Figs. 1–4.