A 2.1-kb genomic fragment of the 5'-flanking region/promoter of the mouse Keratin 19 gene drives expression of the full-length human K-ras gene with a point mutation in codon 12 that alters a Gly residue to a Val in the encoded protein. An intronic fragment from the rabbit beta-globin gene was inserted between the promoter and mutated KRAS gene to enhance gene expression. In addition to line A, lines B and C were also created. (J:83092)