FIG. 4.

A mutant allele of groE reduces the cellular amount of Pol IV protein in the absence of LexA. Shown is a Western blot indicating the levels of Pol IV in (from left to right): PFG324 [sulA lexA(Def)], PFG325 [sulA lexA(Def) groEL100], PFG326 (sulA), FC526 (dinB⁺⁺), and FC1240 [Δ(dinB)]. PFG324, PFG325, and PFG326 are F⁻ strains, so their only dinB alleles are chromosomal; these strains are also sulA11 [which prevents lethal filamentation due to the lexA(Def) allele]. Only one blot is shown, but lanes with irrelevant samples have been removed. Samples consisting of 40 μg of total protein were loaded. The intensities of the bands for each strain relative to those of the wild-type strain are given below each lane.