MAIL, a novel nuclear I kappa B protein that potentiates LPS-induced IL-6 production

We have identified and characterized a novel member of the ankyrin-repeat f amily named 'molecule possessing ankyrin-repeats induced by lipopolysacchar ide' (MAIL). The C-terminal portion of MAIL shared high sequence homology,v ith the I kappaB family. Intraperitoneal injection of lipopolysaccharide (L PS) into mice rapidly (< 0.5 h) induced MAIL mRNA in various tissues, parti cularly in the spleen, lymph node, and lung. Ectopically expressed MAIL was localized in the nucleus, and remarkably potentiated the LPS-induced mRNA expression and secretion of interleukin (IL)-6 in Swiss 3T3 cells, These fi ndings indicate that MAIL is one of the nuclear I<kappa>B proteins and an a ctivator of IL-6 production. (C) 2000 Federation of European Biochemical So cieties. Published by Elsevier Science B.V. All rights reserved.