Characterization of the pleiotropic phenotypes of rifampin-resistant rpoB mutants of Escherichia coli

Abstract

We used our collection of 17 sequenced rifampin resistance alleles in rpoB to perform a systematic analysis of the phenotypes historically reported with this class of mutants, including growth phenotype, ability to support the growth of different bacteriophages, ability to maintain the F' episome, interaction with mutant alleles at other loci, sensitivity to uracil, inhibition by 5-fluorouridine, and dominance. We found that mutational changes leading to the same phenotype were often located together and that certain phenotypes were associated with one another.Historically, Escherichia coli rpoB mutations that confer rifampin resistance (Rif) have been used to probe the involvement of RNA polymerase in a variety of physiological processes. Rif' mutations have been found to affect a wide variety of phenotypes, including altered growth properties (10, 16); the ability to support the growth of various bacteriophages (12,18,19); the ability to maintain the F' episome (4); interaction with mutant alleles dnaA(Ts) (2), rpoD(Ts) (15), and strA24 (3); and uracil sensitivity (13). We used our collection of 17 sequenced Rif' mutations (8)

The rpoB mutants destabilizing initiation complexes at stringently controlled promoters behave like “stringent” RNA polymerases in Escherichia coli

“…Overall, the nature of the defects of these mutant RNAPs interacting with these four stringent promoters is comparable, although the degree of the defect of each mutant RNAP at each promoter is not necessarily the same. Such a defect might be responsible for the slow-growth phenotypes of these rpoB mutants (9). At present, we do not know which step in initiation is defective at these promoters for the mutant RNAPs.…”

“…Recently, we found that four rpoB mutations [rpoB114(S531F), rpoB3449(⌬532A), rpoB3443(L533P), and rpoB3370(T563P)] (7), which are among previously characterized Rif r alleles (8,9), have specifically reduced the transcription from the two major promoters, P1 and P2, of the rpoD operon (10,11), leading to a hyper-temperature-sensitive phenotype of a 70 mutant (9). Because these two promoters are negatively controlled by the stringent response (12), it suggests that these rpoB mutants have specifically altered interaction with stringent promoters.…”

RNA polymerase mutants found through adaptive evolution reprogram Escherichia coli for optimal growth in minimal media

“…kinetics | stringent response | transcription M utations to the primary RNAP genes in bacteria (rpoABCZ encoding the core α, β, β′, and ω subunits and rpoD encoding the housekeeping σ 70 subunit) exhibit a wide range of pleiotropic effects on bacterial phenotypes (1)(2)(3)(4)(5), and it has been said that mutations to RNAP genes can satisfy virtually any selection (6). We recently described the discovery of mutations in rpoB and rpoC following adaptive evolution of Escherichia coli K-12 MG1655 in glycerol M9 minimal medium (GMM) over a period of several weeks (7).…”

Spontaneous antibiotic resistance mutation associated pleiotropic changes in Escherichia coli O157:H7

“…At the same time, however, motility, flagellin production, growth rate, sensitivity towards certain phages and the virulence of Rif r mutant strains have been changed. Pleiotropic effect is often the result of rpoB mutation (Jin and Gross, 1989), which most frequently determines rifampicin resistance (Jin and Gross, 1988). Earlier Yamamori et al (1977) described nitrosoguanidine-induced Rif r mutation associated pleiotropic phenotypes in E. coli K-12.…”

“…In E. coli rifampicin resistance (Rif r ) is associated with specific nucleic acid substitutions in the gene encoding for RNA polymerase subunit β (rpoB) described by Jin and Gross (1988) and it has been found that rifampicin-resistant rpoB mutants cause pleiotropic phenotypes including growth phenotypes, ability to support different bacteriophages, ability to maintain the F' episome, interaction with mutant alleles at other loci, sensitivity to uracil, inhibition by 5-fluorouridine, and dominance recorded by Jin and Gross (1989). On the basis of these observations rifampicin-and ampicillin-resistant mutants were isolated and the motility, the production of FliC protein and flagella and the virulence of these antibiotic-resistant derivative strains were compared.…”