Skip to main content
. 2009 Jun 2;284(30):19856–19866. doi: 10.1074/jbc.M109.025817

FIGURE 4.

FIGURE 4.

ZBTB5 competes with p53 in binding to the distal p53 binding elements and increases Sp1 binding to the GC-box 5/6 in vivo. A, structure of the endogenous p21 gene. Distal p53 binding elements and proximal GC-rich elements are indicated. Arrows indicate binding positions of the qChIP oligonucleotide primers. Tsp +1, transcription start site. UTR, untranslated region. B and C, qChIP assay of binding competition between p53 and FLAG-ZBTB5 on the distal p53 binding regions of endogenous p21 in HEK293A cells. ZBTB5 competed with p53 in binding to the elements. The cells were transfected with increasing amounts (0–6 μg) of FLAG-ZBTB5 expression vector. D, qChIP assay of FLAG-ZBTB5 and Sp1 binding on the proximal promoter region of endogenous p21 in HEK293A cells. ZBTB5 increases Sp1 binding to the elements. The cells were transfected with increasing amounts of FLAG-ZBTB5 expression vector (0–6 μg). Antibodies against FLAG tag, p53, Sp1, and IgG were used in ChIP assays.