Figure 2.

Dependence of total Bgl⁺ mutations and IS insertional Bgl⁺ mutations on BglG levels. A total of 2 × 10⁷ cells of strain R_Ptet-G were applied on M9 + salicin agar plates with various levels of aTc (the inducer for TetR-repressed Ptet). The Bgl⁺ mutations were carried out as for Figure 1. (A) Diagram showing TetR inhibition of bglG expression and BglG activation of Bgl⁺ mutations. As an inducer, aTc releases TetR from the Ptet promoter, thereby allowing bglG expression. The more aTc added, the greater the expression of bglG. In the absence of an inducer (aTc), no additional BglG (BglG production is only from the native bgl operon) is produced. (B) Effects of titrated bglG expression on total Bgl⁺ mutations. (C) Effects of BglG levels on the ratios of IS insertional mutants out of the total number of Bgl⁺ mutants.