a, Experimental design. AP, alkaline phosphatase; IP, immunoprecipitation; iTRAQ, isobaric tag for relative and absolute quantification; MS, mass spectrometry. b, The lentiviral vector construct to conditionally regulate Nanog expression levels7. dLTR, deleted long-terminal repeat; FLAP, nucleotide segment that improves transduction efficiency; Teton, tetracycline transactivator; WRE, woodchuck hepatitis virus post-transcriptional regulatory element. c, Efficacy of Nanog protein downregulation as measured by mass spectrometry (bar chart) and western blot (image, bottom). Error bars denote the s.d. of duplicate measurements. d, Summary of the numbers of genes with significant changes at different molecular layers on each day. Increased and decreased levels are shown in orange and green, respectively.