DNA microarrays of SKOM transduced MEFs with added Tgfb1 or co-expressing Snail

The Tgf-b signaling pathway plays an important role in both embryonic development and epithelial to mesenchymal transition (EMT), but the influence of this pathway and its relationship with EMT in fibroblast reprogramming is not defined. Using Affymetrix mouse genome array and mouse embryonic fibroblast cells (MEFs), we analyzed the expression profiles of Tgf-b1 and one of its important mediators in EMT, Snail, regulated genes at Day 10 during the process of reprogramming. A total of 535 genes were differentially expressed (2-fold change) in cells activated by Tgf-b1 and 970 genes were differentially expressed in cells over-expressing Snail. Among them, 170 genes were shared in both categories. The differentially expressed genes involve in many biological processes, including Tgf-b signaling pathway, cell communication, ECM-receptor interaction, cell adhesion, focal adhersion, and Hedgehog signaling pathway MEFs derived from a OG2 mouse is a typical kind of fibroblast cells used in most reprogramming studies. Cells were cultured in MEF medium in an incubator with 5% CO2 at 37oC before retrovirus infection and the medium was changed into ES medium after infection of the reprogramming cocktail (Sox2, Klf4, Oct4 and cMyc). At Day 10 after infection, cells were collected and total RNA were extracted from the cells and was hybridized on Affymetrix GeneChip Mouse Genome 430 2.0 Array.