Figure 2.

Rcn1p family members inhibit calcineurin function in yeast. (A) Overexpression of yeast RCN1, human DSCR1, or human ZAKI4 genes in yeast blocked calcineurin-dependent inhibition of Vcx1p, thereby restoring growth to pmc1 mutants but not pmc1 vcx1 mutants in high calcium medium (YPD at pH 5.5 + 200 mm CaCl₂). Photographs of colonies were taken after two days incubation at 30°C. (B) Overexpression of RCN1 inhibited calcineurin-dependent induction of PMC1–lacZ. Reporter gene expression was monitored in pmc1 vcx1 double mutants carrying either empty vector or RCN1 overexpression plasmid after 4 hr growth in medium supplemented with 100 mm CaCl₂ and 0.3 μm FK506 as indicated. Expression was also monitored in wild-type strains containing a constitutively active Tcn1p(C)–Gal4(DB) transcription factor. (C) Overexpression of RCN1, DSCR1, or ZAKI-4 inhibited expression of CDRE–lacZ. Betagalactosidase assays were performed as indicated in B.