(A).. Undifferentiated hESCs carrying Oct-4-driven eGFP (green) express Oct-4 and differentiated hESCs after treated with HADC inhibitor TSA express Nestin (red) and phalloidin (green). (B).. Undifferentiated hESC colonies, as indicated by SSEA-4 expression (red), express nuclear localized p300 (red) and cytoplasmic localized Tip60 (green) and HADC4 (green). (C). Undifferentiated hESCs maintained under the defined culture in the presence of bFGF and insulin have a heavily acetylated chromatin as suggested by strong immunopositivity to acetylated histone H4 (AcH4, green), Myc (red), and HATs Tip60 (green) and p300 (red). When either bFGF or insulin is omitted, the differentiated cells show significantly reduced immunoreactivity to AcH4, Myc, Tip60, and nuclear focal localization of p300. All cells are indicated by DAPI staining of their nuclei (blue).