FIGURE 5.

Phylogenetically conserved HiRE XI is essential for the transcriptional repression of CXCR7. A, nucleotide sequence of the 5′ region of the human CXCR7 gene showing the mutation introduced into the conserved HiRE XI site (TGC in the core motif replaced by CAT) to impede HIC1 binding (5). B, reporter constructs schematically shown in the left panel were transfected in triplicate into U2OS cells and assayed for luciferase activity. Luciferase (luc) activity is shown in the right panel (gray boxes). Repression of transcription of each construct by HIC1 was calculated exactly as detailed in legend to Fig. 4B. Results, expressed relative to a value of 1.0 for cells transfected with the pGL3 empty vector, are expressed as the mean of four different experiments, and error bars represent standard deviations. The p values are indicated (*, p values < 0.5; **, p values < 0.05). C, same experiments were performed with the −813/+168 wild-type and ΔXI constructs. The results are the mean of two independent transfections in triplicate with the p value indicated as in B.