Two waves of nuclear factor kappa B recruitment to target promoters

Proinflammatory stimuli induce the rapid and transient translocation of nuc lear factor (NF)-kappaB to the nucleus, where it activates transcription fr om several genes, including those encoding inflammatory cytokines and chemo kines, adhesion molecules, and cytoprotective proteins. Using chromatin imm unoprecipitation, we show that after an acute stimulation two; distinct wav es of NF-kappaB recruitment to target promotes occur: a fast recruitment to constitutively and immediately accessible (CIA) promoters and a late recru itment to promoters requiring stimulus-dependent modifications in chromatin structure to make NF-kappaB sites accessible (promoters with regulated and late accessibility [RLA]). Our results suggest that a mechanism of specifi city in NF-kappaB-dependent transcriptional responses relies on the ability of individual stimuli to make RLA promoters accessible to NF-kappaB before its rapid extrusion from the nucleus.