Figure 3
From: Novel STAT binding elements mediate IL-6 regulation of MMP-1 and MMP-3
Identification of a HDLC binding non-canonical SBEs in MMP-1 and MMP-3 promoters. (A) Extracts from SW480 or HepG2 cells treated with IL-6 (50 ng/ml, 5 min) or IFN-γ (1000 U/ml, 1 h) were probed with the sis-inducible element (SIE) oligonucleotide. Arrows indicate the STAT-3 homodimer, the STAT-1/STAT-3 heterodimer and the STAT-1 homodimer. Also shown is binding of a novel STAT-1 HDLC constitutively to the MMP-1 SBE/AP-1 and MMP-3 SBE I/AP-1 probes. (B) EMSA showing a similar STAT-1 HDLC constitutively binding to the MMP-3 SBE II/III and MMP-3 SBE IV probes using extracts from HepG2 cells treated with PMA (100 nM, 90 min), IL-6 (50 ng/ml, 5 min) and IFN-γ (1000 U/ml, 60 min). (C) EMSA in the presence of anti-STAT-1, anti-pan-Fos and anti-c-Jun antibodies, respectively, as indicated. (D) EMSA of MMP1 (SBE) and (SBE/AP-1), MMP-3 (SBEI) and (SBE I/AP-1) probes using HepG2 cell extracts in the presence and absence of 1 μg poly-dI:dC showing dependence of STAT-1 HDLC binding on the AP-1 site. For (A–D), experiments were repeated showing similar results.
