Only cells that express a puromycin-resistance (PR) gene can grow in the presence of the drug puromycin. Ganciclovir is a nontoxic drug that is converted to a lethal toxin in a cell that expresses thymidine kinase (TK). Thy-1 is a fibroblast-specific marker protein. Which of the following selection strategies is the most reasonable one to use in experiments that attempt to generate induced pluripotent stem cells (iPS cells) from fibroblasts (1 point, letter)? Explain your choice (4 points, 2-3 sentences).
Engineering fibroblasts to express PR under the control of the Nanog promoter, and selecting iPS cells in puromycin-containing media
Engineering fibroblasts to express PR under the control of the Thy-1 promoter, and selecting iPS cells in puromycin-containing media
Engineering fibroblasts to express TK under the control of the Nanog promoter, and selecting iPS cells in ganciclovir-containing media
Engineering fibroblasts to express TK under the control of the Thy-1 promoter, and selecting iPS cells in ganciclovir-containing media
Engineering fibroblasts to express TK under the control of the Thy-1 promoter, and selecting iPS cells in puromycin-containing media