BOTH N-TERMINAL AND C-TERMINAL DOMAINS OF RELB ARE REQUIRED FOR FULL TRANSACTIVATION - ROLE OF THE N-TERMINAL LEUCINE ZIPPER-LIKE MOTIF

RelB, a member of the Rel family of transcription factors, can stimulate promoter activity in the presence of p50-NF-kappaB or p50B/p49-NF-kappaB 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-KB. RelB/p50-NF-kappaB hybrid molecules containing the Rel homology domain of p50-NF-kappaB and the N and C termini of RelB have high transcriptional activity compared with wild-type p50-NF-kappaB. 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 Re]B and of different RelB/p50-NF-kappaB hybrid molecules.