Coordinated induction of antigen transport and immunoproteasome gene expression in response to CD40 ligation. (A) Schematic representation of the TAP1/LMP2 bidirectional promoter and of the promoter regions of the TAP2, tapasin, and LMP10 genes. The sequences and relative positions of putative IRF-Es and NF-κB binding elements in relation to the transcription start sites are depicted. The consensus motif for IRF-1 is (G/C)(A)AAA(N)2-3AAA(G/C)(T/C) (60), and that for NF-κB is GGGRNNYYCC, where R represents purine, Y represents pyrimidine, and N indicates any base (45). Numbers above the diagrams indicate nucleotide positions relative to the transcription start sites. (B) Induction of antigen transporter and immunoproteasome gene expression following CD40 stimulation. EJ cells were treated with CD40L or, as a control, IFN-γ for the indicated times, and isolated RNA was subjected to RT-PCR using primers specific for the TAP1, LMP2, TAP2, tapasin, or LMP10 gene or the GAPDH housekeeping gene. Data are representative of results from five independent experiments for TAP1 and three experiments for LMP2, TAP2, tapasin, and LMP10. −, absent; 15′, 15 min.