Fig. 4
Two CaCrz1-binding motifs in the promoter play additive roles in the regulation of CaUTR2 expression. (a), β-galactosidase activities of the wild-type promoter UTR2-lacZ in the wild-type SN148 and the crz1/crz1 mutant cells in the absence or presence of 0.2 M CaCl2. The asterisk (*) indicates statistically significant differences (P < 0.05) in the β-galactosidase activity between the wild type strain SN148 and the crz1/crz1 mutant strain in the absence or presence of 0.2 M CaCl2, respectively. (b), β-galactosidase activities of the wild-type promoter UTR2-lacZ, two single mutated promoters UTR2(HΔ)-lacZ and UTR2(MΔ)-lacZ as well as the double mutated promoter UTR2(HMΔ)-lacZ in the wild-type SN148 cells in the absence or presence of 0.2 M CaCl2. The asterisks (#) and (*) indicate statistically significant differences (P < 0.05) in the β-galactosidase activity between the wild type promoter and each of the mutated promoters in the wild-type strain SN148 in the absence or presence of 0.2 M CaCl2, respectively