3A and B). Various polarization conditions also influenced the chromatin conformation at the TNF TSS. Mouse CD4+ cells polarized under Th1 and Th17 conditions demonstrated a significant chromatin opening at the TNF TSS, while Th2 polarization resulted in a more closed chromatin configuration (Fig. 3C). Th0 cells cultured Selleckchem LY2157299 with immobilized anti-CD3 antibodies (Th0i) had somewhat more open conformation at TNF TSS than Th0 cells cultured with soluble anti-CD3 antibodies (Th0s) (Fig. 3C). Polarized Th1 and Th17 cell subsets also demonstrated elevated levels of activating histone H3 lysine 4 3-methylation (H3K4me3) (Fig. 3D and Supporting Information Fig. 4A). In contrast to polarized T cells, we did not

find any difference in the level of H3K4me3 modification between quiescent and activated T cells (Supporting Information

Fig. 4B). To find out if any of buy PD-0332991 the major TCR-activated transcription factors were involved in chromatin remodeling at TNF TSS, pull-down assay from the total lysate of EL4 T cells stimulated for 3 h with PMA and ionomycin was applied utilizing DNA probes spanning several regulatory elements of the TNF gene, including proximal promoter/TSS, enhancer in TNF intron 3, and enhancer downstream of TNF gene (3′TNF enhancer). Biotinylated amplicon from LT-α exon 4 was used as negative control. We evaluated binding of c-Jun, JunB, c-Fos, and ATF-2 members of AP-1 family; NFATc2 (NFAT1) and NFATc1 (NFAT2) members of NFAT family; and RelA/p65 and c-Rel members of NF-κB family of transcription factors (Fig. 4A). As a result, selective binding of NFATc2 and c-Jun to the amplicon covering the proximal promoter/TSS of the mouse TNF gene was observed in accordance with previous reports [24-29, 49-51]. Such interactions at TNF proximal promoter/TSS appeared to be evolutionary conserved and were observed also in human T cells [28, 52]. Some c-Rel binding to the proximal promoter/TSS of TNF

was also detected (Fig. 4A). Surprisingly, in contrast to previous reports, we observed relatively weak binding of ATF-2 to the mouse TNF proximal promoter (Fig. 4A) [28, 29, 50, 51]. To confirm interaction of NFATc2 and c-Jun with proximal promoter/TSS of TNF, we performed chromatin immunoprecipitation assay (Fig. 4B and C). Increased binding GABA Receptor of these transcription factors (including pS73 form of c-Jun) at TNF proximal promoter (−174 −55) and TSS (−50 +73) was observed after stimulation of naive T cells with anti-CD3/anti-CD28 (Fig. 4B). We also observed stronger binding of c-Jun to the proximal promoter/TSS of TNF in quiescent Th1 and Th17 in comparison to Th0 and Th2 cells (Fig. 4C). Unpolarized cells, cultured with immobilized anti-CD3 antibodies (Th0i), showed intermediate level of binding of c-Jun with TNF proximal promoter/TSS (Fig. 4C), correlating with more open (in comparison with Th0s cells) TNF TSS conformation (Fig. 3C).