Cloning of the murine relA (p65 NF-kappa B) gene and comparison to the human gene reveals a distinct first intron

A murine genomic clone encoding the relA (p65 NF-kappa B) locus was isolated and characterized. The clone spanned about 20 kb and included at least 10 exons and the relA promoter. Sequencing of the promoter region revealed the presence of a murine-specific intron of 546 bp intervening the homologue of human exon 1. The species-specific organisation of relA genes and promoter elements is compared and discussed. Despite the presence of potential binding sites for transcription factors NF-kappa B and AP-1 in the murine relA promoter, the constitutive relA transcript level was not affected by treatment of cells with phorbol ester or pyrrolidinedithiocarbamate, compounds which strongly affect NF-kappa B and AP-1 activities. This provides pharmacological evidence that the relA gene is not inducibly controlled by NF-kappa B or AP-1.