Escherichia coli K12 Strain JW5917-1, an rcsC Knock Out Strain in the Keio Collection, Displays an Impaired Growth Phenotype Compared to its Isogenic Parent Strain BW25113

The Regulator of Capsule Synthesis (Rcs) phosphorelay pathway regulates the expression of genes necessary for biofilm formation and stress response within
Enterobacteriaceae. RcsC, an inner membrane sensor kinase, autophosphorylates during periods of antibiotic stress, osmotic stress, and nutrient deprivation. This leads to activation of downstream components, such as rprA and RpoS, which are important for regulating the stress response. Previous work has suggested a linkage between the Rcs pathway and resistance to antibiotics targeting the cell wall. In this study, we characterized the Keio collection knockout mutants JW5917-1, JW0192-1, JW2204-1, JW2205-2 which encode deletions of rcsC, rcsF, rcsD and rcsB, respectively. Using PCR and Sanger sequencing we mapped the site-specific insertion of the kanamycin-resistance cassette defining the ΔrcsC mutant. We observed reduced growth yields associated with the ΔrcsC mutant, which
appear to be a distinct phenotype relative to the wildtype parent strain BW25113. We also observed that the ΔrcsF mutant shows increased sensitivity to penicillin compared to the other Δrcs strains.