Influence of 3' half-site sequence of NF-κB motifs on the binding of lipopolysaccharide-activatable macrophage NF-κB proteins

Lipopolysaccharide treatment of mouse macrophage-like J774 cells was found to result in the activation of three different nuclear proteins which specifically bind to oligonucleotide containing the NF-κB motif of the human immunodeficiency virus (HIV) gene. These are designated as NF-κB1, -κB2, and -κB3, according to their electrophoretic mobilities (fast, intermediate, and slow, respectively). Immunological and UV cross-linking studies showed that NF-κB1 consists of only p50 subunit, whereas both NF-κB2 and -κB3 contain NF-κB p65 subunit and c-Rel. In addition, NF-κB2 was also found to contain p50 subunit of NF-κB. The binding of three types of NF-κB proteins to HIV NF-κB motif was effectively inhibited by other NF-κB motifs, whose 3' half-site nucleotide sequences are T/A-T-T/C-CC (HIV, interleukin-6, interferon (INF)-β, H2-K^b, I-Eα(d), and TNF-α2 (nucleotide position - 510)) and much less effectively by NF-κB motifs with 3' half-site sequences of TGCCC (TNF-α3, nucleotide position -610), ATCTC (G-CSF), TATTC (FcγR), or TCCTT (TNF-α1, nucleotide position -850). Our data also suggested that NF-κB1 and -κB2 which contain p50 subunit of NF-κB bind with the higher preference for NF-κB motif of H2-K^b gene promoter than that of INF-β, whereas NF-κB3 which does not contain p50 subunit appears to preferentially bind to NF-κB sites of IFN-β.