The DNA binding domain common to members of zebrafish E4BP4 or Forkhead (Fkd) families were each expressed in E. coli, partially purified under non-denaturing conditions, and tested for specific binding to their recognition sequences identified in and around the zebrafish appb gene. Panel A: E4BP4 protein, indicated below each lane in μg, added to Fkd probe (f), lanes 1–3, or the E4BP4 probe (e), lanes 4–8. Panel B: Fkd protein, indicated below each lane in μg, added to Fkd probe (f), lanes 1–4, or E4BP4 probe (e), lanes 5–7. Panel C: E4BP4 protein binding to probes (a through f) spanning upstream E4BP4 sites (a-d), E4BP4 site in intron 1 enhancer (e), and Fkd site in intron enhancer (f). E4BP4 protein used in each lane (μg) is indicated on right. Probes (b-d) correspond to cluster of three E4BP4 sites at −31 kb.
Shakes et al. BMC Genomics 2012 13:451 doi:10.1186/1471-2164-13-451