Figure 1. The TRPM7-like current is dramatically reduced in trpm7^b508 mutants.

Representative whole-cell current recordings of melanophores isolated at 32 hpf, in A) control or B) trpm7 mutant embryos, in response to voltage ramps from −100 mV to +100 mV for 500 ms. A) Control melanocytes exhibited outwardly rectifying currents that are potentiated by the extracellular application of 10 mM NH₄Cl, and inhibited by the application of 10 mM MgCl₂, properties that are characteristic of TRPM7-mediated currents. B) The mutant melanophores did not exhibit any TRPM7-like outwardly rectifying currents. The slight outward rectification of currents in mutant melanophores indicates that the cells were alive. Control, n=7 cells; mutant, n=3 cells.