Table 2.

Effects of glucose and snf1 on repression by LexA fusion proteins

ReporteraRelevant genotypebExpressed proteinGrowth conditioncβ-Galactosidase activity (Miller units)dFold repression
Without lexA operatorsWithlexA operators
CYC1-lacZ WTLexA-Mig1High Glu1706.825
LexA-Ssn6High Glu2307.630
LexA-Mig1ΔZHigh Glu1308.116
Low Glu3701402.6
LexA87 High Glu180911.9
Low Glu1,1203902.9
snf1 LexA-Mig1ΔZHigh Glu5.10.413
Low Glu4.70.316
LexA87 High Glu3.71.62.3
Low Glu2.02.01.0
LEU2-HIS3-lacZ WTLexA-Mig1High Glu958.311
LexA87 High Glu94851.2
  • a The CYC1-lacZ reporter contains either no lexA operators (pLGΔ312S [18]) or four lexA operators (JK1621 [27]) 5′ to the UAS. LEU2-HIS3-lacZcontains the lacZ gene under the control of theLEU2 UAS and the HIS3 promoter with either nolexA operators (pBM2762 [40]) or onelexA operator (pMT27) 5′ to the UAS.

  • b WT, wild type. Strains were MCY829, MCY3912, and MCY2692.

  • c Strains were grown selectively in 5% glucose (high Glu) or 2% raffinose plus 0.05% glucose (Raf). Cells were also shifted from 5 to 0.05% glucose for 3 h (low Glu).

  • d β-Galactosidase activity was assayed in permeabilized cells. Values represent the averages of results for 3 to 24 transformants. Standard errors were <20%.