An IRES-eGFP cassette and a cDNA sequence encoding Ikbkb containing two serine to glutamate substitutions in the activation loop of the kinase domain, preceded by a floxed stop-neo cassette was inserted into the locus. The Ikbkb would be expressed under the control of the endogenous ROSA26 promoter after cre-mediated excision of the STOP cassette. (J:113365)