Fig. 7. Human MRP1 can substitute for C. elegans MRP-1 in dauer larva regulation. (A) The dauer larva formation of the unc-31(e169);mrp-1(ut153) double mutant was suppressed efficiently by an extrachromosomal array of the wild-type human MRP1 cDNA driven by the C. elegans mrp-1 promoter. (B) The suppression of dauer larva formation by human MRP1 cDNA was partially antagonized by the human MRP1 inhibitor PAK-104P. (C) The suppression of dauer larva formation by C. elegans mrp-1 genomic DNA was not antagonized by PAK-104P. The means of three plates (42-107 animals/plate) are shown. As PAK-104P was dissolved in DMSO, the final concentration of DMSO is shown in the figure. Animals carrying an extrachromosomal array of transgenes segregated those that had lost the extrachromosomal array. Dauer formation of these animals was also examined and is shown as a control on the left of each data set.