ABSTRACT: We aimed to define epithelial-specific genes in the kidney. In the developing mouse kidney at E12.5 epithelial cells are restricted to the ureteric bud, while mesenchymal cells surrounding the ureteric bud are non-epithelial. The mouse renal epithelial cell line mIMCD-3 was used to represent kidney epithelia in vitro. Gene expression was analyzed using Affymetrix microarrays in ureteric bud stalks, ureteric bud tips, and mIMCD-3 cells and compared to metanephric mesenchyme. Affymetrix Mouse Genome 430 2.0 microarrays from mouse E12.5 ureteric bud tips, ureteric bus stalks, and metanephric mesenchymes had previously been published (GEO deposition: GDS1583) (Schmidt-Ott, K. M., Yang, J., Chen, X., Wang, H., Paragas, N., Mori, K., Li, J. Y., Lu, B., Costantini, F., Schiffer, M. et al. (2005). Novel regulators of kidney development from the tips of the ureteric bud. J Am Soc Nephrol 16, 1993-2002.). We added a new microarray analysis from a subclone of mIMCD-3 cells and recalculated expression values in the complete dataset by robust multichip analysis.