Fig. 1.

PU.1 binds to the endogenous lipocalin-prostaglandin D synthase (L-PGDS) promoter in response to LPS treatment. A: scheme represents the sequences of the murine L-PGDS promoter. Nucleotides were numbered backward from the transcription initiation site of the promoter. A putative PU.1 binding site (c-Ets-1) is shown in the box, and there is no other significant transcription factor binding site in this segment of the promoter. The 10th nucleotide in every 10-count is shown in italic bold. A set of primers flanking the putative PU.1 site, which was used for PCR for a chromatin immunoprecipitation (ChIP) assay, is underlined. B: bone marrow-derived macrophages (BMDM) were treated with LPS (1 μg/ml) for indicated time points for a ChIP assay. DNA bound to PU.1 was precipitated with an α-PU.1 antibody. For exclusion of nonspecific immunoprecipitation, an isotypic IgG was added to the lysate of the cells treated with LPS for 4 h (lane 5). Precipitated DNA and genomic DNA (bottom) were amplified by PCR with the same set of primers described in A. C: BMDM of C57BL/6 mice treated with either PBS (lane 1) or LPS (1 μg/ml) for 16 h (lane 2) were analyzed by Western blotting for L-PGDS, hematopoietic-type prostaglandin D synthase (H-PGDS), and actin after stripping the L-PGDS blot.