Structure of the murine TRAF1 gene.

We have cloned, characterized and sequenced the murine TNF Receptor Associated Factor 1 (TRAF1) gene. Restriction mapping and Southern blotting analysis revealed that the TRAF1 gene comprises 10 exons and 9 intervening introns and spreads over 18 kb of genomic DNA. 5'-RACE analysis of the TRAF1 transcript using mRNA from activated spleen B cells revealed several transcription start sites between positions -42 to +4 relative to the 5'end of the murine TRAF1 cDNA sequence. We also isolated and sequenced the 5'-upstream promoter region, which lacks TATA-like and CAAT-like sites but contains GC-rich sequences. Taken together, these results suggest that the TRAF1 gene promoter is a member of the class of Sp-1-dependent promoters. Near the transcription initiation start site we identified three identical decanucleotide repeats (CCAGCCCAGC) which may play a role in the transcriptional regulation of TRAF1 expression. In addition we show that TRAF1 mRNA is not expressed in non-stimulated lymphocytes but can be induced upon activation with different stimuli, including anti-CD3, anti-IgM, anti-CD40 antibodies, LPS, or a combination of phorbol-12-myristate-13-acetate and ionomycin.