NF-κB (REL) homologues in scup (Stenotomus chrysops) and possible activation of NF-κB by AH receptor agonists

Rel family proteins, p50, p52, RelA, RelB, and cRel, constitute dimeric nuclear factor-κB (NF-κB) transcription factors NF-κB rapidly activates genes encoding cytokines, cell surface receptors, cell adhesion molecules and acute phase proteins NF-κB is activated by stimuli including reactive oxygen species (ROS). We examined Rel proteins and NF-κB activation by xenobiotics in the fish scup, partly because of findings that PCBs stimulate ROS release from scup CYP1A DNA-protein cross-linking revealed specific binding of an NF-κB consensus sequence by liver, kidney and heart nuclear proteins from untreated fish Two of the three proteins identified corresponded to mouse p50 and RelA Antibodies to p50 immunoprecipitated the 50 kD protein RT-PCR cloning of a Rel homology domain from scup liver confirmed the presence of a Rel sequence Gel shift assays showed that NF-κB activation occurred in vehicle-treated fish, but that this decreased over time 3,3′,4,4′,5-Pentachlorobiphenyl (0.01–1 mg/kg) stimulated 6–8-fold increases in activation 16–18 days after treatment, but a second experiment showed no significant activation 14 days after treatment The data establish that Rel family proteins, including a p50 homologue, occur in fish, and that activation by Ah receptor agonists may occur but is variable. [EPA R823890-01, NIH ES-17381 and a WHOI-Mellon Award.]