A recessive mutant cell line with a constitutive IκB kinase activity

Abstract
To search for negative regulatory components of the NF-kappaB activation pathways, we mutagenized Rat-1 fibroblasts and established a stable mutant cell line with a constitutive NF-kappaB activity. This mutant cell line, designated as TK26, showed permanently elevated I kappa B kinase (IKK) activity and a genetically recessive phenotype revealed by somatic cell hybridization between TK26 and Rat-1. Our results suggested that lack of a negative regulation of IKK could lead to permanent NF-kappaB activation. The TK26 cell line will be useful to genetically identify a component necessary for keeping the IKK complex under an inactive form in resting cells.