Figure 1.

Factors affecting CXCL1 gene transcription. The CXCL1 promoter contains binding sites for factors that bind to these sites. They either increase (shown in red) or decrease (shown in blue) CXCL1 expression. In particular, the CXCL1 promoter contains a binding site for STAT1 and Sp1. STAT1 and Sp1 activated by IFN-γ and TNF-α, respectively, attach to these sites. Sp1 increases CXCL1 expression; however, STAT1 inhibits Sp1 binding to the CXCL1 promoter. Another mechanism regulating CXCL1 expression is IUR, a region that directly borders the NF-κB binding site. CDP binds to IUR, which inhibits the recruitment of CBP and PCAF coactivators by NF-κB. This prevents the induction of CXCL1 expression by NF-κB.