TABLE 3

Roles of cAMP signaling and pH response pathways in white-to-opaque switchinga

StrainWhite-to-opaque switching frequency (%) at pH:
4.05.06.07.07.58.0
WT18.4 ± 2.9*12.5 ± 0.913.8 ± 0.3*5.4 ± 1.0*<1.0<1.3
cyr1/cyr1b23.5 ± 3.3*7.1 ± 4.1*4.8 ± 1.32.4 ± 3.4Growth defectGrowth defect
pde2/pde2100.0100.0100.0*93.8 ± 2.374.2 ± 1.8*67.5 ± 1.2
phr1/phr12.7 ± 1.8*0.2 ± 0.4<0.20.2 ± 0.4<0.3<0.3
PHR1 reconstituted9.4 ± 0.1*5.9 ± 0.4*2.9 ± 1.1*0.9 ± 0.8*<0.50.6 ± 1.0
phr2/phr2Growth defectGrowth defect0.9 ± 1.23.8 ± 3.2*0.8 ± 1.1<0.9
PHR2 reconstituted5.8 ± 0.310.4 ± 2.3*4.7 ± 0.8*0.5 ± 0.8*<0.5<0.6
rim101/rim1012.4 ± 0.76.0 ± 0.8*1.7 ± 0.82.6 ± 0.63.8 ± 2.34.2 ± 0.2
RIM101 reconstituted10.0 ± 2.8*6.4 ± 1.34.6 ± 1.4*0.7 ± 1.2*<0.4<0.4
  • a The WT was strain GH1013, an SC5314 background strain. White cells were plated onto Lee's glucose medium plates and incubated in air at 25°C for 7 days. Assays for the quantitation of white-to-opaque switching frequencies were performed. <, no opaque or opaque-sectored colonies were observed. PHR1, PHR2, or RIM101 reconstituted, a copy of the PHR1, PHR2, or RIM101 gene, respectively, was integrated into the original locus. *, statistically significant difference (Student's t test, P < 0.05; see footnote a of Table 1).

  • b The cyr1/cyr1 mutant grew extremely slowly. The switching frequencies were examined after 12 days of growth.