Planarian regeneration depends on the presence of pluripotent stem cells in the adult.We developed an in vivo COUNTRY CHEDDAR W PASTA BROCCOLI stable isotope labeling by amino acids in cell culture (SILAC) protocol in planarians to identify proteins that are enriched in planarian stem cells.Through a comparison of SILAC proteomes of normal and stem cell-depleted planarians and of a stem cell-enriched population of sorted cells, we identified hundreds of stem cell proteins.One of these is an ortholog of nuclear receptor coactivator-5 (Ncoa5/CIA), which is known to regulate estrogen-receptor-mediated transcription in human cells.We show that Ncoa5 is essential for the maintenance of the pluripotent stem cell population in planarians and that a putative mouse ortholog is expressed in pluripotent cells of the embryo.
Our study thus identifies ROM Handle a conserved component of pluripotent stem cells, demonstrating that planarians, in particular, when combined with in vivo SILAC, are a powerful model in stem cell research.