The FRSV motif of the endogenous Wnk locus has been mutated to AASV (the mutation also introduces a silent NheI site). A sequence cassette encoding a Disc\RFPDsRed(T1).3xP3.cHa marker flanked by termini from the Tni\piggyBac transposable element has also been inserted. The encoded protein includes 20 residues from Wnk after the AA mutation, and then 8 novel amino acids from the inserted sequence cassette, followed by a stop codon.