IMF-κB and Rel: Participants in a Multiform Transcriptional Regulatory System

This chapter highlights NF-кB/Rel protein complex. Associations of the binding and regulatory subunits of NF-кB operate at the center of a variety of different signal pathways. NF-кB can process and integrate instructions that come from the extracellular environment and detect intracellular events originating in either the cytoplasm or the nucleus. NF-кB then transmits this information with astonishing rapidity to the transcriptional machinery by directly binding to a range of different DNA sequences in gene control regions. NF-кB comprises members of a family of dimer-forming proteins with homology to the rel oncogene. NF-кB has the striking appearance of being constitutively present only in B cells of the “appropriate” stage for Ig к light chain gene expression. The functional role of NF-кB is demonstrated by mutational analysis of the к intronic enhancer. The property that gives NF-кB a widespread significance in cellular regulation is its role as a mediator of inducible gene transcription. The key features of NF-кB transcriptional control are that it is fast and versatile and is used in many different gene systems. It also has the important ability to carry signals from the cytoplasm into the nucleus and trans-activate specific genes by binding directly to their promoters.