Figure 2.

The helicase regions provide the FRH functions that are essential for growth. (A) Race tube assay of wild type and FRH^R806H shown as three representative race tubes grown with the three concentrations of inducer (QA). (B) Strain genotypes of experimental strains (bottom eight groups of three): Linkage group 1; at the csr-1 locus: mutant versions of frh driven by the frh promoter. Linkage group 2; at the frh native locus: frh driven by the QA-inducible qa-2 promoter. (C) Race tube assay of qa-2 driven FRH and the mutant knock-ins at the csr-1 locus. Each strain contains an inducible copy of wt frh as well as a native promoter-driven but mutated copy of frh at the csr-1 locus and is shown as three representative race tubes grown with the three concentrations of inducer (QA). Less than wild type growth rate indicates a level of functional FRH inadequate for full rescue of essential functions. Restoration of growth indicates that the induced wt FRH was able to supply the essential functions (QA[] = concentration of QA, τ= period in hours, σ = standard deviation, n = number of race tubes, GR = growth rate in mm/day).