The human BRAF cDNA with a thymine-to-adenine transversion at position 1799A leading to a valine-to-glutamate substitution at residue 600 (V600E) and an NH2-terminal myc tag are under the control of the thyroid-specific bovine thyroglobulin promoter. Quantitative RT-PCR and Western blot analysis confirmed mRNA and protein expression in thyroid tissue. This is the lower expressing line.