Growth phase-dependent transcription of emrKY, a homolog of multidrug efflux emrAB, genes of Escherichia coli, is induced by tetracycline.

Tanabe, Hiroyuki; Yamasaki, Katsuhide; Furue, Motoki; Yamamoto, Kanehisa; Katoh, Akinori; Yamamoto, Masanori; Yoshioka, Setsuko; Tagami, Hideaki; Aiba, Hirofumi; Utsumi, Ryutaro

doi:10.2323/jgam.43.257

Cited by 33 publications

(24 citation statements)

References 22 publications

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“…Some of the AGG_AGG-or AGA_AGA-containing genes are most likely not expressed under standard conditions but become activated depending on growth medium and physiological state. This is certainly true for emrK, the drug efflux gene that we used for comparison studies, the transcription of which is dependent on the drug presence and growth phase (16,40,60). Thus, at a given time, most likely only a subset of these genes is expressed, and the total amount of mRNAs containing AG A_AGA (or AGG_AGG) is likely to be somewhat lower than that from the P araB promoter used in the current study (at 0.02% arabinose induction).…”

Section: Discussionmentioning

confidence: 99%

Expression Levels Influence Ribosomal Frameshifting at the Tandem Rare Arginine Codons AGG_AGG and AGA_AGA in Escherichia coli

et al. 2005

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The rare codons AGG and AGA comprise 2% and 4%, respectively, of the arginine codons of Escherichia coli K-12, and their cognate tRNAs are sparse. At tandem occurrences of either rare codon, the paucity of cognate aminoacyl tRNAs for the second codon of the pair facilitates peptidyl-tRNA shifting to the ؉1 frame. However, AGG_AGG and AGA_AGA are not underrepresented and occur 4 and 42 times, respectively, in E. coli genes. Searches for corresponding occurrences in other bacteria provide no strong support for the functional utilization of frameshifting at these sequences. All sequences tested in their native context showed 1.5 to 11% frameshifting when expressed from multicopy plasmids. A cassette with one of these sequences singly integrated into the chromosome in stringent cells gave 0.9% frameshifting in contrast to two-to four-times-higher values obtained from multicopy plasmids in stringent cells and eight-times-higher values in relaxed cells. Thus, ؉1 frameshifting efficiency at AGG_AGG and AGA_AGA is influenced by the mRNA expression level. These tandem rare codons do not occur in highly expressed mRNAs.

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Section: Discussionmentioning

confidence: 99%

Expression Levels Influence Ribosomal Frameshifting at the Tandem Rare Arginine Codons AGG_AGG and AGA_AGA in Escherichia coli

et al. 2005

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“…Colony dot blot DNA hybridization studies were performed to test if marA sequence homology was present in the 44 Salmonella serotypes. The serotypes tested were Agama, Agona, Anatum, Arizonae, Binza, Bovis morbificans, Bradenburg, Bredeney, Cubana, Derby, Dublin, Ealing, Enteritidis, Give, Gold Coast, Hadar, Harford, Heidelberg, Idikan, Indiana, Infantis, Kedougou, Kentucky, Lexington, London, Manhattan, Mbandaka, Montevideo, Muenster, Newington, Newport, Ohio, Oranienberg, Orion, Panama, Poona, Pullorum, Senftenberg, Taksony, Tennessee, Thompson, Typhimurium, Virchow, and Wangata.…”

Section: Methodsmentioning

confidence: 99%

Multiple Antibiotic Resistance ( mar ) Locus in Salmonella enterica Serovar Typhimurium DT104

Randall¹,

Woodward²

2001

Appl Environ Microbiol

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In order to understand the role of the mar locus in Salmonella with regard to multiple antibiotic resistance, cyclohexane resistance, and outer membrane protein F (OmpF) regulation, a marA::gfp reporter mutant was constructed in an antibiotic-sensitive Salmonella enterica serovar Typhimurium DT104 background. Salicylate induced marA, whereas a number of antibiotics, disinfectants, and various growth conditions did not. Increased antibiotic resistance was observed upon salicylate induction, although this was shown to be by both mardependent and mar-independent pathways. Cyclohexane resistance, however, was induced by salicylate by a mar-dependent pathway. Complementation studies with a plasmid that constitutively expressed marA confirmed the involvement of mar in Salmonella with low-level antibiotic resistance and cyclohexane resistance, although the involvement of mar in down regulation of OmpF was unclear. However, marA overexpression did increase the expression of a ca. 50-kDa protein, but its identity remains to be elucidated. Passage of the marA::gfp reporter mutant with increasing levels of tetracycline, a method reported to select for mar mutants in Escherichia coli, led to both multiple-antibiotic and cyclohexane resistance. Collectively, these data indicate that low-level antibiotic resistance, cyclohexane resistance, and modulation of OMPs in Salmonella, as in E. coli, can occur in both a mar-dependent and mar-independent manner.

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“…Recently we cloned all of them and investigated their drug resistance phenotypes (K. Nishino and A. Yamaguchi, unpublished data). During the course of that study, we found that the DNA locus including a putative transporter emrKY gene system (21) and two-component signal transduction evgA and -S genes (22) conferred multidrug resistance of E. coli. The emrK and -Y genes exhibit sequence similarity to the emrA and -B genes encoding a multidrug exporter of E. coli (10), although the transport capabilities of EmrK and Y have not been elucidated.…”

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confidence: 99%

Overexpression of the Response Regulator evgA of the Two-Component Signal Transduction System Modulates Multidrug Resistance Conferred by Multidrug Resistance Transporters

2001

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Growth phase-dependent transcription of emrKY, a homolog of multidrug efflux emrAB, genes of Escherichia coli, is induced by tetracycline.

Cited by 33 publications

References 22 publications

Expression Levels Influence Ribosomal Frameshifting at the Tandem Rare Arginine Codons AGG_AGG and AGA_AGA in Escherichia coli

Expression Levels Influence Ribosomal Frameshifting at the Tandem Rare Arginine Codons AGG_AGG and AGA_AGA in Escherichia coli

Multiple Antibiotic Resistance ( mar ) Locus in Salmonella enterica Serovar Typhimurium DT104

Overexpression of the Response Regulator evgA of the Two-Component Signal Transduction System Modulates Multidrug Resistance Conferred by Multidrug Resistance Transporters

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