Expression data from cells at reprogramming day 3, 5 and 7. Expression data from cells at reprogramming day 3, 5 and 7

The protein level of OCT4, a core pluripotency transcriptional factor, is vital for embryonic stem cell (ESC) maintenance, differentiation and somatic cell reprogramming. Although OCT4 protein is regulated at multiple scales, the role and regulatory mechanisms of OCT4 ubiquitination in reprogramming remains elusive. We identified the five lysine residues as ubiquitination sites on OCT4, and found that destruction of the ubiquitination can enhance OCT4 activity in reprogramming. We used microarrays to detail the global gene expression underlying cellular reprogramming induced by two sets of reprogramming factor combinations, including O(WT)SK and O(5R)SK, and identified distinct pattern of gene expression change during this process. Overall design: Reprogramming cells, induced by transcription factor combination of O(WT)SK or O(5R)SK, were collected at successive stages at day 3, 5, and 7 for RNA extraction and hybridization on Affymetrix microarrays.