Fig. 1.

Identification of transcription factors that are important for differentiation. a Relative numbers of significantly upregulated (UP) and downregulated (DN) transcription factors (TF) in specific normal tissues relative to human embryonic stem cells (hESC). In the case of lung, kidney and colon, fetal tissue was used to ensure that the comparison is not confounded by age effects. b As a but now expressing the relative numbers of differentially expressed TFs as fractions and comparing these fractions with those of 1000 randomly selected genes (RND). P values are from a one-tailed Fisher’s exact test, demonstrating that most differentially expressed bivalently marked transcription factors in hESCs become upregulated upon differentiation. c Distribution of log2 fold changes (log2(FC)) for the significantly upregulated TFs in each tissue type, demonstrating that most upregulated TFs exhibit at least twofold changes in expression. d Upregulated TFs, identifying common and “tissue-specific” TFs