Inducible activation of RelB in fibroblasts

RelB, a member of NF-kappaB/Rel family of transcriptional regulators, is an immediate-early gene product that mediates constitutive lymphoid-specific kappaB-directed gene expression. Data presented here show that RelB also functions as a mitogen-inducible DNA binding activity in fibroblasts. Activation of RelB was observed in three mouse fibroblast lines, and agents activating RelB in quiescent and cycling cells included platelet-derived growth factor, phorbol ester, and serum. Additional data implicate cyclic AMP in the regulation of RelB activity. These findings suggest that RelB may play different roles in different cell types.