Molecular differentiation of common promoters in Salmonella class 1 integrons

Kim, Tae‐Eun; Kwon, Hyuk‐Joon; Cho, Sunhee; Kim, Shukho; Lee, Bok-Kwon; Yoo, Han Sang; Park, Taesung; Kim, Sun-Joong

doi:10.1016/j.mimet.2006.09.019

Cited by 17 publications

(16 citation statements)

References 25 publications

(33 reference statements)

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“…P C2 is enabled by a GGG insertion (on the top strand) that increases the distance between the -35 box sequence and a sequence resembling the -10 box consensus from 14 to 17 bp, thereby generating a functional σ70 promoter [3,4,50,51]. In all its reported instances, this GGG insertion disrupts a seemingly functional LexA binding site.…”

Section: Resultsmentioning

confidence: 99%

Prevalence of SOS-mediated control of integron integrase expression as an adaptive trait of chromosomal and mobile integrons

et al. 2011

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BackgroundIntegrons are found in hundreds of environmental bacterial species, but are mainly known as the agents responsible for the capture and spread of antibiotic-resistance determinants between Gram-negative pathogens. The SOS response is a regulatory network under control of the repressor protein LexA targeted at addressing DNA damage, thus promoting genetic variation in times of stress. We recently reported a direct link between the SOS response and the expression of integron integrases in Vibrio cholerae and a plasmid-borne class 1 mobile integron. SOS regulation enhances cassette swapping and capture in stressful conditions, while freezing the integron in steady environments. We conducted a systematic study of available integron integrase promoter sequences to analyze the extent of this relationship across the Bacteria domain.ResultsOur results showed that LexA controls the expression of a large fraction of integron integrases by binding to Escherichia coli-like LexA binding sites. In addition, the results provide experimental validation of LexA control of the integrase gene for another Vibrio chromosomal integron and for a multiresistance plasmid harboring two integrons. There was a significant correlation between lack of LexA control and predicted inactivation of integrase genes, even though experimental evidence also indicates that LexA regulation may be lost to enhance expression of integron cassettes.ConclusionsAncestral-state reconstruction on an integron integrase phylogeny led us to conclude that the ancestral integron was already regulated by LexA. The data also indicated that SOS regulation has been actively preserved in mobile integrons and large chromosomal integrons, suggesting that unregulated integrase activity is selected against. Nonetheless, additional adaptations have probably arisen to cope with unregulated integrase activity. Identifying them may be fundamental in deciphering the uneven distribution of integrons in the Bacteria domain.

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Section: Resultsmentioning

confidence: 99%

Prevalence of SOS-mediated control of integron integrase expression as an adaptive trait of chromosomal and mobile integrons

et al. 2011

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“…bla was present in C. youngae CyB38 (from the People's Republic of China) as a single cassette. Restriction digests (9) and/or sequencing revealed variants of the class 1 integron promoter Pc (3,11) in isolates from different locations. There was no correlation between the previously defined Pc promoter strength (3,11) and the imipenem MIC (Table 1), which is host strain dependent (5).…”

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bla _IMP-4 in Different Genetic Contexts in Enterobacteriaceae Isolates from Australia

Espedido

Partridge

Iredell

2008

Antimicrob Agents Chemother

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The IMP-4 metallo-␤-lactamase, originally recognized in Acinetobacter spp. from Hong Kong, more recently appeared simultaneously in isolates of the family Enterobacteriaceae from Sydney and Melbourne, Australia. The bla IMP-4 -qacG2-aacA4-catB3 cassette array was found in isolates from both cities, but in different wider genetic contexts and on different plasmids, suggesting movement of this array by homologous recombination.

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“…Among the same gene cassettes, some nucleotide changes tend to be present, and some of these are shared by other bacteria. Certain of those nucleotide changes can be classified as singlenucleotide polymorphisms (SNPs), and these have proven useful in the fine differentiation of bacterial isolates, as well as in studies of the molecular evolution of class 1 integrons (19,32). Gene cassettes lack their own promoters, and their expression levels are affected by their proximity to the common promoter, P ant (P1), the strength of promoter P1, and the presence of P2 (9).…”

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confidence: 99%

“…On the basis of promoter activity, P1 promoters can be classified as strong, hybrid, or weak promoters, and the insertion of 3 guanosines 119 nucleotides downstream of P1 results in the creation of a new, weak promoter, designated P2 (9,13,22). Thus far, integron studies have focused primarily on the contents of gene cassettes and have largely overlooked their common promoter structures (19).…”

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confidence: 99%

Chronological Study of Antibiotic Resistances and Their Relevant Genes in Korean Avian Pathogenic Escherichia coli Isolates

Kim¹,

Jeong²,

Cho

et al. 2007

J Clin Microbiol

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Antibiograms and relevant genotypes of Korean avian pathogenic Escherichia coli (APEC) isolates (n ‫؍‬ 101) recovered between 1985 and 2005 were assessed via disc diffusion test, PCR, restriction enzyme analysis, and sequencing. These isolates were highly resistant to tetracycline (84.2%), streptomycin (84.2%), enrofloxacin (71.3%), and ampicillin (67.3%), and most of the tetracycline, streptomycin, enrofloxacin, and ampicillin resistances were associated with tetA and/or tetB, aadA and/or strA-strB, mutations in gyrA and/or parC, and TEM, respectively. Class 1 integrons were detected in 40 isolates (39.6%), and a variety of gene cassettes conferring streptomycin (aadA), gentamicin (aadB), and trimethoprim (dfr) resistances were identified: aadA1a (27.5%), dfrV-orfD (2.5%), aadB-aadA1a (2.5%), dfrI-aadA1a (47.5%), dfrXVII-aadA5 (12.5%), and dfrXII-orfFaadA2 (7.5%). In addition, several types of common promoters (P ant ) of the gene cassettes (hybrid P1, weak P1, or weak P1 plus P2) and single-nucleotide polymorphisms in aadA1a were identified. The results of a chronological analysis demonstrated significant and continuous increases in the frequencies of resistances to several antibiotics (tetracycline, streptomycin, enrofloxacin, ampicillin, and trimethoprim-sulfamethoxazole) and of the relevant resistance genes (tetA, strA-strB, and TEM), mutations in gyrA and parC, and multidrugresistant APEC strains during the period 2000 to 2005.

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Molecular differentiation of common promoters in Salmonella class 1 integrons

Cited by 17 publications

References 25 publications

Prevalence of SOS-mediated control of integron integrase expression as an adaptive trait of chromosomal and mobile integrons

Prevalence of SOS-mediated control of integron integrase expression as an adaptive trait of chromosomal and mobile integrons

bla _IMP-4 in Different Genetic Contexts in Enterobacteriaceae Isolates from Australia

Chronological Study of Antibiotic Resistances and Their Relevant Genes in Korean Avian Pathogenic Escherichia coli Isolates

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Molecular differentiation of common promoters in Salmonella class 1 integrons

Cited by 17 publications

References 25 publications

Prevalence of SOS-mediated control of integron integrase expression as an adaptive trait of chromosomal and mobile integrons

Prevalence of SOS-mediated control of integron integrase expression as an adaptive trait of chromosomal and mobile integrons

bla IMP-4 in Different Genetic Contexts in Enterobacteriaceae Isolates from Australia

Chronological Study of Antibiotic Resistances and Their Relevant Genes in Korean Avian Pathogenic Escherichia coli Isolates

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bla _IMP-4 in Different Genetic Contexts in Enterobacteriaceae Isolates from Australia