In this system, primary iPS cells were generated first by infection of neonatal tail-tip fibroblasts, carrying the ROSA-rtTA transactivator, with lentiviruses expressing Oct4, Sox2, Klf4 and cMyc, each under the control of a doxycycline (dox)-inducible promoter (Figure S1) [14]. The gene discussed is POU5F1; the disease is infection.