Figure 1.

A, Schematic structure of the DMI1 protein and relative position of the stop codons in the dmi1-1, dmi1-2, and dmi1-3 alleles. The dmi1-4 allele contains a complete deletion of the 5′ end of the gene. TM, Transmembrane domain; nTP, nuclear targeting peptide as demonstrated by Riely et al. (2007). B, The dmi1-2 mutant allele is defective in Mas7-induced Ca²⁺ spiking. Cells of wild-type and mutant lines were microinjected with the Ca²⁺-responsive dye Oregon green and the nonresponsive dye Texas red. Ca²⁺ changes were measured as the ratio of Oregon green to Texas red, allowing pseudoratiometric imaging of Ca²⁺ changes in Mas7-treated cells. The y axis represents the ratio of Oregon green to Texas red in arbitrary units. Representative traces are shown. The numbers indicate the numbers of Mas7-responsive cells per total number of cells analyzed.