The kinetics of barrier genes in IPS competent cells during reprogramming

In order to ascertain the dynamics of screen hits in iPS cell progenitors during intermediate stages of reprogramming we compared TRA-1-81+ screen hits to their mouse orthologs in the gene expression and epigenetic state data from Polo et al. as well as the protein concentration data from Hansson et al. Both Polo and Hansson reprogrammed secondary MEFs by dox-inducible viral expression of Yamanaka factors. On days 3, 6, 9, 12, and 15 cells were FACS-purified based on Thy1, SSEA-1, and exogenous Oct4-GFP expression, in order to enrich for potential iPS cells. On those days, Polo assayed gene expression by microarray and Hansson identified and quantified proteins by LC-MS/MS. Additionally, on days 3, 9, 12, and 15 Polo identified the genome wide binding of H3K4me3 and H3K27me3, via ChIP-seq.