The complete coding sequence of mouse AQP2 from an IMAGE clone was digested from the pCMV⋅SPORT6 plasmid with EcoRI and NotI and ligated into pcDNA3.1 (Invitrogen, Carlsbad, California, United States). The F204V mutation was introduced by site-directed mutagenesis (Stratagene, La Jolla, California, United States), using the sense oligonucleotide 5′-GATGATCACTGGGTCGTCTGGATCGGACCCC-3′, and antisense oligonucleotide 5′-GGGGTCCGATCCAGACGACCCAGTGATCATC-3′. To generate GFP fusions of AQP2, the pCMV⋅SPORT6 AQP2 construct was used in a PCR reaction with the primers Sp6 and 5′-GACTGGATCCCGGCCTTGCTGCCGCGCGGCAG-3′ to remove the stop codon of AQP2. The product was digested with KpnI and BamHI and ligated into pEGFP-N2 (BD Biosciences, San Diego, California, United States). The F204V mutation was introduced using the same mutagenic oligonucleotides.