A Transient transfection of Elf5 increases the endogenous Avpr2 and Aqp2 transcript levels in mpkCCDC14 cells as determined by RT-qPCR. B. RT-qPCR reveals that Elf5 expression is essentially absent in Cdh16->Cre; Elf5f/* mouse neonatal kidneys compared with wild type littermates, where * denotes floxed (f) or null allele. In the absence of Elf5 expression, Avpr2 and Aqp2 expression are reduced to 75% of wild type levels on average, p<0.05, n= 6 wild type and 8 Cdh16-Cre;Elf5f/*. C. The percentage of collecting duct cells that express Aqp2 is not significantly different in the cortex, outer medulla and inner medulla of Elf5-deficient collecting ducts compared with similar regions in the kidneys of wild-type littermates at post-natal day one (P1), n>6 40X images per region of kidney for each mouse and 3 mice per genotype. Images of P1 kidney sections from Elf5f/f (D–F) and Cdh16->Cre;Elf5f/* (G–I) stained for Aqp2 and CAII to determine the percentage of principal and intercalated present in the collecting ducts. Scale bars are 10μm. (J) Collecting duct segment specific genes are not expressed at significantly different levels in the Cdh16->Cre;Elf5f/* mouse neonatal kidneys compared with wild type littermate kidneys as determined by RT-qPCR, n= 5 per group.