Gene expression profiling of Lgr5 positive cells within intestinal adenomas

The generation of the Lgr5_EGFP_ires_CreERT2 knock-in mouse allows marking of Lgr5 positive cells of different tissues. Here we use these mice to sort Lgr5 positive cells and their daughter cells form intestinal adenomas and describe the expression profile of these two cell populations. Intestinal adenomas were generated by inducing Apc deletion through tamoxifen injection in Apc_fl/fl-Lgr5_EGFP_ires_CreERT2 mice. In these mice, GFP is expressed under the control of the Lgr5 promoter, leading to highest GFP levels in Lgr5 positive cells (GFP-high). Dividing GFP-high cells pass on Gfp two their daughter cells, thereby diluting the GFP. Daughter cells can therefore be isolated based on their lower GFP positivity (GFP-low). We sorted these two cell fractions (GFP-high and GFP-low) and compared them to each other on 4X44K Agilent Whole Mouse Genome dual colour Microarrays (G4122F). Three independent sorts were performed and RNA of GFP-high cells hybridized directly against RNA of GFP-low cells in three dye swap experiments, resulting in six individual arrays.