MODULATION OF TRANSCRIPTION FACTOR NF-KAPPA-B BINDING-ACTIVITY BY OXIDATION REDUCTION INVITRO

NF-kappa-B is a widely used regulator of inducible and tissue-specific gene control. In the cytosol, when complexed to an inhibitory molecule, I-kappa-B, NF-kappa-B is in an inactive form and cannot bind DNA. Activation of cells with appropriate stimuli results in the dissociation of NF-kappa-B from I-kappa-B and its translocation to the nucleus as an active binding protein. We now demonstrate that NF-kappa-B binding in vitro can be inhibited by agents that modify free sulfhydryls. Binding is eliminated after treatment with N-ethylmaleimide, an alkylating agent, and diamide, an oxidizing agent. The diamide effect can be reversed by 2-mercaptoethanol. Further, 2-mercaptoethanol acts synergistically with deoxycholate plus Nonidet P-40 in converting inactive cytosolic NF-kappa-B to an active DNA-binding form. It is therefore possible that modulation of the redox state of NF-kappa-B could represent a post-translational control mechanism for this factor.