Novel transcriptional regulation of the schlafen-2 gene in macrophages in response to TLR-triggered stimulation.

Schlafen-2 (slfn-2) is a member of slfn family, regulators of T cell development and its expression is altered during infection by microbial pathogens. However, the molecular mechanism involved in slfn expression is still to be determined. In this study, we isolated slfn-2 as a LPS-induced differentially expressed genes (DEGs) in RAW 264.7 cells and examined expression and regulation of slfn-2 in CpG-DNA-treated and LPS-treated macrophages. We defined a transcriptional start site in the slfn-2 gene. To examine the promoter organization of the slfn-2 gene, we cloned a approximately 1.8 kb region upstream of the transcription start site. Sequence analysis indicates consensus sites for AP-1 and NF-kappaB. Comprehensive mutant analyses, ELISA-based transcription factor activation assay, and ChIP assays reveal that functional interaction of AP-1 and NF-kappaB with the promoter element is necessary for the Toll-like receptor (TLR)-mediated slfn-2 gene expression by CpG-DNA and LPS treatment in macrophages. In summary, we identified a slfn-2 promoter for the first time and demonstrated that CpG-DNA and LPS triggers slfn-2 gene expression by activating NF-kappaB and AP-1 pathways in macrophages.