PKD1 and cyst: To identify differentially expressed transcripts that are most specifically correlated with cyst formation, we combined analysis from mice with three genotypes: Pkd1 single mutants (Pkd1KO) that are genetically destined to develop polycystic kidney disease19, Pkd1 and Kif3a (Pkd1KO+ciliaKO) double knockouts that are protected from cyst growth despite inactivation of Pkd119,22, and Pkd1 heterozygous mice that behave like wild type (“noncystic”) (Fig. 1a).