Genetic organization of multiple fep genes encoding ferric enterobactin transport functions in Escherichia coli.

Prokaryotic genes encoding functionally related proteins are often clustered in operons. The compact structure of operons allows for co-transcription of the genes, and for co-translation of the polycistronic messenger RNA to the corresponding proteins. This leads to reduced regulatory complexity and enhanced gene expression efficiency, and as such to an overall metabolic benefit for the protein production process in bacteria and archaea. Interestingly, the genes encoding the subunits of one of the most conserved and ubiquitous protein complexes, the RNA polymerase, are not clustered in a single operon. Rather, its genes are scattered in all known prokaryotic genomes, generally integrated in different ribosomal operons. To analyze the impact of this genetic organization on the fitness of Escherichia coli, we constructed a bacterial artificial chromosome harboring the genes encoding the RNA polymerase complex in a single operon. Subsequent deletion of the native chromosomal genes led to a reduced growth on minimal medium. However, by using adaptive laboratory evolution the growth rate was restored to wild-type level. Hence, we show that a highly conserved genetic organization of core genes in a bacterium can be reorganized by a combination of design, construction and optimization, yielding a well-functioning synthetic genetic architecture.

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Faculty Opinions recommendation of IscR, an Fe-S cluster-containing transcription factor, represses expression of Escherichia coli genes encoding Fe-S cluster assembly proteins.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1002791.46105 ◽

2002 ◽

Author(s):

Regine Hengge

Keyword(s):

Escherichia Coli ◽

Transcription Factor ◽

Cluster Assembly ◽

Genes Encoding ◽

Assembly Proteins

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Faculty Opinions recommendation of Genetic screen yields mutations in genes encoding all known components of the Escherichia coli signal recognition particle pathway.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.1003128.30060 ◽

2001 ◽

Author(s):

Koreaki Ito

Keyword(s):

Escherichia Coli ◽

Signal Recognition Particle ◽

Genetic Screen ◽

Signal Recognition ◽

Genes Encoding

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Differential translation of the genes encoding the proton-translocating ATPase of Escherichia coli.

Journal of Biological Chemistry ◽

10.1016/s0021-9258(19)83880-2 ◽

1986 ◽

Vol 261 (18) ◽

pp. 8096-8099

Author(s):

D J Klionsky ◽

D G Skalnik ◽

R D Simoni

Keyword(s):

Escherichia Coli ◽

Genes Encoding ◽

Proton Translocating Atpase

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Molecular Epidemiology of NDM-1-Producing Enterobacteriaceae and Acinetobacter baumannii Isolates from Pakistan

Antimicrobial Agents and Chemotherapy ◽

10.1128/aac.02425-14 ◽

2014 ◽

Vol 58 (9) ◽

pp. 5589-5593 ◽

Cited By ~ 25

Author(s):

Anna L. Sartor ◽

Muhammad W. Raza ◽

Shahid A. Abbasi ◽

Kathryn M. Day ◽

John D. Perry ◽

...

Keyword(s):

Escherichia Coli ◽

Molecular Epidemiology ◽

Genetic Relatedness ◽

Antibiotic Resistance Genes ◽

Enterobacter Cloacae ◽

Content Type ◽

Plasmid Replicon ◽

Genes Encoding ◽

Clonal Spread ◽

Encoding Genes

ABSTRACTThe molecular epidemiology of 66 NDM-producing isolates from 2 Pakistani hospitals was investigated, with their genetic relatedness determined using repetitive sequence-based PCR (Rep-PCR). PCR-based replicon typing and screening for antibiotic resistance genes encoding carbapenemases, other β-lactamases, and 16S methylases were also performed. Rep-PCR suggested a clonal spread ofEnterobacter cloacaeandEscherichia coli. A number of plasmid replicon types were identified, with the incompatibility A/C group (IncA/C) being the most common (78%). 16S methylase-encoding genes were coharbored in 81% of NDM-producingEnterobacteriaceae.

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Shiga Toxins, and the Genes Encoding Them, in Fecal Samples from Native Idaho Ungulates

Applied and Environmental Microbiology ◽

10.1128/aem.01158-08 ◽

2008 ◽

Vol 75 (3) ◽

pp. 862-865 ◽

Cited By ~ 8

Author(s):

Jeremy J. Gilbreath ◽

Malcolm S. Shields ◽

Rebekah L. Smith ◽

Larry D. Farrell ◽

Peter P. Sheridan ◽

...

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Wild Ungulates ◽

Fecal Samples ◽

Shiga Toxins ◽

Toxin Genes ◽

Genes Encoding ◽

Shiga Toxin Genes

ABSTRACT Cattle are a known reservoir of Shiga toxin-producing Escherichia coli. The prevalence and stability of Shiga toxin and/or Shiga toxin genes among native wild ungulates in Idaho were investigated. The frequency of both Shiga genes and toxin was similar to that reported for Idaho cattle (∼19%).

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PCR cloning, sequence analysis and expression of the cybC genes encoding soluble cytochrome b-562 from Escherichia coli B strain OP7 and K strain NM522

Biochimica et Biophysica Acta (BBA) - Bioenergetics ◽

10.1016/0005-2728(93)90223-3 ◽

1993 ◽

Vol 1143 (1) ◽

pp. 109-111 ◽

Cited By ~ 10

Author(s):

Michael K. Trower

Keyword(s):

Escherichia Coli ◽

Sequence Analysis ◽

Cytochrome B ◽

Pcr Cloning ◽

Genes Encoding ◽

Escherichia Coli B

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Characteristics of Shiga Toxin–Producing Escherichia coli Isolated from Swiss Raw Milk Cheese within a 3-Year Monitoring Program

Journal of Food Protection ◽

10.4315/0362-028x-73.1.88 ◽

2010 ◽

Vol 73 (1) ◽

pp. 88-91 ◽

Cited By ~ 36

Author(s):

C. ZWEIFEL ◽

N. GIEZENDANNER ◽

S. CORTI ◽

G. KRAUSE ◽

L. BEUTIN ◽

...

Keyword(s):

Escherichia Coli ◽

Shiga Toxin ◽

Monitoring Program ◽

Raw Milk ◽

Health Impact ◽

Toxin Gene ◽

Genes Encoding ◽

Raw Milk Cheese ◽

Human Infections ◽

Hard Cheese

Food is an important vehicle for transmission of Shiga toxin–producing Escherichia coli (STEC). To assess the potential public health impact of STEC in Swiss raw milk cheese produced from cow's, goat's, and ewe's milk, 1,422 samples from semihard or hard cheese and 80 samples from soft cheese were examined for STEC, and isolated strains were further characterized. By PCR, STEC was detected after enrichment in 5.7% of the 1,502 raw milk cheese samples collected at the producer level. STEC-positive samples comprised 76 semihard, 8 soft, and 1 hard cheese. By colony hybridization, 29 STEC strains were isolated from 24 semihard and 5 soft cheeses. Thirteen of the 24 strains typeable with O antisera belonged to the serogroups O2, O22, and O91. More than half (58.6%) of the 29 strains belonged to O:H serotypes previously isolated from humans, and STEC O22:H8, O91:H10, O91:H21, and O174:H21 have also been identified as agents of hemolytic uremic syndrome. Typing of Shiga toxin genes showed that stx1 was only found in 2 strains, whereas 27 strains carried genes encoding for the Stx2 group, mainly stx2 and stx2vh-a/b. Production of Stx2 and Stx2vh-a/b subtypes might be an indicator for a severe outcome in patients. Nine strains harbored hlyA (enterohemorrhagic E. coli hemolysin), whereas none tested positive for eae (intimin). Consequently, semihard and hard raw milk cheese may be a potential source of STEC, and a notable proportion of the isolated non-O157 STEC strains belonged to serotypes or harbored Shiga toxin gene variants associated with human infections.

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Ferric uptake regulator (Fur) reversibly binds a [2Fe-2S] cluster to sense intracellular iron homeostasis in Escherichia coli

Journal of Biological Chemistry ◽

10.1074/jbc.ra120.014814 ◽

2020 ◽

Vol 295 (46) ◽

pp. 15454-15463 ◽

Cited By ~ 1

Author(s):

Chelsey R. Fontenot ◽

Homyra Tasnim ◽

Kathryn A. Valdes ◽

Codrina V. Popescu ◽

Huangen Ding

Keyword(s):

Escherichia Coli ◽

Iron Content ◽

Iron Homeostasis ◽

Ferric Uptake Regulator ◽

Intracellular Iron ◽

Free Iron ◽

E Coli ◽

Genes Encoding ◽

Fur Protein ◽

Mutant Cells

The ferric uptake regulator (Fur) is a global transcription factor that regulates intracellular iron homeostasis in bacteria. The current hypothesis states that when the intracellular “free” iron concentration is elevated, Fur binds ferrous iron, and the iron-bound Fur represses the genes encoding for iron uptake systems and stimulates the genes encoding for iron storage proteins. However, the “iron-bound” Fur has never been isolated from any bacteria. Here we report that the Escherichia coli Fur has a bright red color when expressed in E. coli mutant cells containing an elevated intracellular free iron content because of deletion of the iron–sulfur cluster assembly proteins IscA and SufA. The acid-labile iron and sulfide content analyses in conjunction with the EPR and Mössbauer spectroscopy measurements and the site-directed mutagenesis studies show that the red Fur protein binds a [2Fe-2S] cluster via conserved cysteine residues. The occupancy of the [2Fe-2S] cluster in Fur protein is ∼31% in the E. coli iscA/sufA mutant cells and is decreased to ∼4% in WT E. coli cells. Depletion of the intracellular free iron content using the membrane-permeable iron chelator 2,2´-dipyridyl effectively removes the [2Fe-2S] cluster from Fur in E. coli cells, suggesting that Fur senses the intracellular free iron content via reversible binding of a [2Fe-2S] cluster. The binding of the [2Fe-2S] cluster in Fur appears to be highly conserved, because the Fur homolog from Hemophilus influenzae expressed in E. coli cells also reversibly binds a [2Fe-2S] cluster to sense intracellular iron homeostasis.

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