WNK1 and leukemia: Treatment of these leukaemia cells with 4-hydroxytamoxifen (OHT) led to recombination of the Wnk1 locus and concomitant loss of WNK1 protein expression (Supplementary Fig. 3b), confirming that WNK1 is essential for the proliferation of these leukaemia cells in vitro (Fig. 3b and Supplementary Fig. 3c).