| NF _kappa_B | A transcription factor (originally found to switch on transcription of genes for the kappa class of immunoglobulins in B lymphocytes). It is involved in activating the transcription of more than 20 genes in a variety of cells and tissues. NF _B is found in the cytoplasm in an inactive form, bound to the protein I_B. A variety of stimuli, such as tumour necrosis factor, phorbol esters and bacterial lipopolysaccharide activate it, by releasing it from I_B, allowing it to enter the nucleus and bind to DNA. It has two subunits p50 and p65 that bind DNA as a heterodimer. The dimerisation and DNA binding activity are located in N terminal regions of 300 amino acid that are similar to regions in the Rel and dorsal transcription factors. (18 Nov 1997) |
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