Characterization of constitutive and inducible transcription factors binding to the P2 NF-AT site in the human interleukin-4 promoter.

摘要: Abstract Interleukin-4 (IL-4) is a pleiotropic immunomodulatory cytokine secreted by T helper 2 cells. The IL-4 promoter contains multiple sites with DNA sequences homologous to the IL-2 NF-AT binding site. One of these sites—the P2 site—located between –173 and –150 was previously found be flanked two octamer-like motifs. NF-ATp/c octamer proteins were suggested bind this region cooperatively activate activity ( Chuvpilo et al., 1993 ). To precisely analyze P2-binding factors we used antibodies against NF-ATp, NF-ATc, Fos, Jun, Oct-1 Oct-2 in EMSA. We show here that nuclear extracts from T-cells form complexes—a PMA/ionomycin-inducible constitutive one. complex NF-ATp/c, Fos Jun. No could detected either complexes. Analysis precise contact points complexes showed both are formed center consensus motif Furthermore, purified recombinant POU domains failed site, suggesting site not an independent octamer-binding Therefore, sequence at for AP-1. Octamer unlikely cooperate © 1997 Elsevier Science B.V. All rights reserved.