POU3F2 and melanoma: We then sequentially stably transduced melanoma cell lines, including two lines with low levels of BRN2, with lentivirus expressing the tetracycline (Tet) repressor followed by BRN2 or lacZ, as a negative control, under the control of the CMV/TetO2 promoter leading to high levels of BRN2 expression (Supplementary Fig. S2).