Both N- and C-Terminal Domains of RelB Are Required for Full Transactivation: Role of the N-Terminal Leucine Zipper-Like Motif

Abstract

RelB, a member of the Rel family of transcription factors, can stimulate promoter activity in the presence of p50-NF-κB or p50B/p49-NF-κB in mammalian cells. Transcriptional activation analysis reveals that the N and C termini of RelB are required for full transactivation in the presence of p50-NF-κB. RelB/p50-NF-κB hybrid molecules containing the Rel homology domain of p50-NF-κB and the N and C termini of RelB have high transcriptional activity compared with wild-type p50-NF-κB. The N and C termini of RelB cooperate in transactivation in cis or trans configuration. Alterations in the structure of the leucine zipper-like motif present in the N terminus of RelB significantly decrease the transcriptional capacity of RelB and of different RelB/p50-NF-κB hybrid molecules.