The effect of rne truncations on growth of a pnp deletion mutant. (A) A wild-type strain (DJ624; WT) or isogenic derivatives harboring a pnp deletion (NRD473 and NRD579; Δpnp) or a pnp deletion and an rne allele truncating the C-terminal domain of rne were streaked onto LB plates that were incubated at 37°C, 32°C, or 25°C. The rne-131 allele encodes an RNase E that lacks residues 585–1061, the complete unstructured C-terminal domain (NRD578; Δpnp rne-131); rneΔ10 lacks residues 844 to 1045, a region that includes the PNPase binding site (NRD 585; Δpnp rneΔ10); rneΔ14 lacks residues 636 to 845, a region that includes the binding site for RhlB and enolase (NRD589; Δpnp rneΔ14). (B) Overnight cultures of the wild-type (wild type) and pnp deletion strain (Δpnp) harboring the wild-type rne allele or the truncated rne alleles listed in A were diluted 200-fold into fresh LB liquid medium and incubated at 37°C and the doubling time during exponential growth determined. These results represent the mean from two independent experiments.
