FIG 2.

P. mirabilis and V. harveyi Crl homologs interact with E. coli σ^S and function in E. coli. (A) β-Galactosidase assay of an osmY promoter-lacZ reporter in E. coli strains with E. coli (Eco), V. harveyi (Vha), or P. mirabilis (Pmi) Crl homologs expressed from a plasmid in a strain with a deletion of crl (Δcrl). (B) BTH analysis to determine interaction between the Eco, Vha, or Pmi Crl homolog expressed as a fusion to λCI and E. coli σ^S₂(WT), an E. coli σ^S₂(E137Q) binding variant, or an unfused control expressed as a fusion to α in a promoter-lacZ reporter strain. β-Galactosidase activity is expressed in Miller units (MU), and the error bars show standard deviations (SD) between 2 separate experiments with 2 independent cultures each.