Sp1-associated activation of macrophage inflammatory protein-2 promoter by CpG-oligodeoxynucleotide and lipopolysaccharide

• DOI: 10.1007/s00018-004-4399-y
• Publication Date: 2005-01-21T17:33:44Z
• Authors: K. -W. Lee; Y. Lee; H. -J. Kwon; D. -S. Kim
• Keywords: Lipopolysaccharides; Transcriptional Activation; 0303 health sciences; Binding Sites; Base Sequence; Proto-Oncogene Proteins c-jun; Sp1 Transcription Factor; Chemokine CXCL2; Molecular Sequence Data; NF-kappa B; Cell Line; Mice; 03 medical and health sciences; Oligodeoxyribonucleotides; Animals; Chemokines; Promoter Regions, Genetic; Sequence Deletion

Macrophage inflammatory protein-2 (MIP-2) is a C-X-C chemokine that is important in recruiting neutrophils to inflammatory sites. Our previous reports demonstrated that lipopolysaccharide (LPS) or CpG-oligode-oxynucleotide (CpG-ODN) rapidly induce MIP-2 gene expression in the macrophage cell line, RAW 264.7. Here, we show that the DNA sequence of the MIP-2 promoter between -114 and +14 is sufficient for strong promoter activity in LPS- or CpG-ODN-stimulated RAW 264.7 cells. Importantly, comprehensive mutant analysis reveals that an Sp1 element in the promoter region between -114 and -94 is essential for synergistic MIP-2 promoter activation by NF-kappaB and c-Jun regardless of the presence of an AP-1 site. By combining deletion or site-specific mutant analysis with immunocomplex assays, we also confirmed that Sp1 mediates the recruitment of transcription factors NF- kappaB and c-Jun in LPS- or CpG-ODN-treated RAW 264.7 cells. Several lines of experimental evidence imply that the Sp1-binding element is an important determinant of MIP-2 promoter activity, and that NF-kappaB, c-Jun and Sp1 can functionally cooperate to elicit maximal activation of the promoter.