Identification of a functional NF-κB binding site in the murine T cell receptor β2 locus

We have identified a sequence in the TCR β2 locus that is homologous to the κB site in the Ig κ light chain enhancer. This element, TCRβ-B, is located in the vicinity of previously identified T cell-specific DNase1 hypersensitive sites. Transfection analysis shows that a 60-bp fragment encompassing this site is preferentially active in T cells stimulated with phorbol esters or the HTLV-1 tax gene product compared with a B cell line that constitutively expresses NF-κB. Our results provide the first evidence for transcriptional regulatory sequences residing within the Jβ2-Cβ2 intron and suggest the possible involvement of these sequences in modulation of TCRβ gene expression upon cellular activation.