A transgene consisting of a 1.8 kb chicken beta-actin promoter, a floxed STOP codon, a mutated KRASVAL12, a polyoma virus internal ribosomal re-entry site, and a fusion molecule consisting of chicken ovalbumin, an S-tag and a luciferase molecule. Expression of the constitutively active oncogenic KRASV12 is dependent on Cre-mediated deletion of the STOP codon. The pound symbol (#) is used because a line number was not specified.