scholarly journals Promoter Characterization and Constitutive Expression of the Escherichia coli gcvR Gene

1998 ◽  
Vol 180 (7) ◽  
pp. 1803-1807 ◽  
Author(s):  
Angela C. Ghrist ◽  
George V. Stauffer
Keyword(s):  
Escherichia Coli ◽  
Transcription Start Site ◽  
Promoter Region ◽  
Start Codon ◽  
Start Site ◽  
Transcription Start ◽  
Translation Start Codon ◽  
Translation Start ◽  
Glycine Cleavage ◽  
Extension Analysis

ABSTRACT The Escherichia coli glycine cleavage repressor protein (GcvR) negatively regulates expression of the glycine cleavage operon (gcv). In this study, the gcvR translational start site was determined by N-terminal amino acid sequence analysis of a GcvR-LacZ fusion protein. Primer extension analysis of thegcvR promoter region identified a primary transcription start site 27 bp upstream of the UUG translation start site and a minor transcription start site approximately 100 bp upstream of the translation start codon. The -10 and -35 promoter regions upstream of the primary transcription start site were defined by mutational analysis. Expression of a gcvR-lacZ fusion was unaltered in the presence of glycine or inosine, molecules known to induce or repress expression of gcv, respectively. In addition, it was shown that gcvR-lacZ expression is neither regulated by the glycine cleavage activator protein (GcvA) nor autogenously regulated by GcvR. From DNA sequence analysis, it was predicted that the translation start codon of the downstream bcp gene overlaps the gcvR stop codon, suggesting that these genes may form an operon. However, a down mutation in the -10 promoter region of gcvR had no effect on the expression of a downstreambcp-lacZ fusion, and primer extension analysis of thebcp promoter region demonstrated that bcp has its own promoter within the gcvR coding sequence. These results show that gcvR and bcp do not form an operon. Furthermore, the deletion of bcp from the chromosome had no effect on gcv-lacZ expression.

scholarly journals Characteristics of the bovicin HJ50 gene cluster in Streptococcus bovis HJ50

Microbiology ◽  
2009 ◽  
Vol 155 (2) ◽  
pp. 584-593 ◽  
Author(s):  
Gang Liu ◽  
Jin Zhong ◽  
Jianqiang Ni ◽  
Meiling Chen ◽  
Haijie Xiao ◽  
...  
Keyword(s):  
Transcription Start Site ◽  
Disulfide Bridge ◽  
Start Codon ◽  
Start Site ◽  
Streptococcus Bovis ◽  
Chromosomal Dna ◽  
Knockout Mutant ◽  
Transcription Start ◽  
Translation Start ◽  
Disulfide Oxidoreductase

Bovicin HJ50 is a new lantibiotic containing a disulfide bridge produced by Streptococcus bovis HJ50; its encoding gene bovA was reported in our previous publication. To identify other genes involved in bovicin HJ50 production, DNA fragments flanking bovA were cloned and sequenced. The bovicin HJ50 biosynthesis gene locus was encoded by a 9.9 kb region of chromosomal DNA and consisted of at least nine genes in the following order: bovA, -M, -T, -E, -F, ORF1, ORF2, bovK and bovR. A thiol–disulfide oxidoreductase gene named sdb1 was located downstream of bovR. A knockout mutant of this gene retained antimicrobial activity and the molecular mass of bovicin HJ50 in the mutant was the same as that of bovicin HJ50 in S. bovis HJ50, implying that sdb1 is not involved in bovicin HJ50 production. Transcriptional analyses showed that bovA, bovM and bovT constituted an operon, and the transcription start site of the bovA promoter was located at a G residue 45 bp upstream of the translation start codon for bovA, while bovE through bovR were transcribed together and the transcription start site of the bovE promoter was located at a C residue 35 bp upstream of bovE. We also demonstrated successful heterologous expression of bovicin HJ50 in Lactococcus lactis MG1363, which lacks thiol–disulfide oxidoreductase genes; this showed that thiol–disulfide oxidoreductase genes other than sdb1 are not essential for bovicin HJ50 biosynthesis.

scholarly journals Determination of the InvE Binding Site Required for Expression of IpaB of the Shigella sonnei Virulence Plasmid: Involvement of a ParB BoxA-Like Sequence

2003 ◽  
Vol 185 (17) ◽  
pp. 5158-5165 ◽  
Author(s):  
Takayuki Taniya ◽  
Jiro Mitobe ◽  
Shu-ichi Nakayama ◽  
Qi Mingshan ◽  
Kenji Okuda ◽  
...  
Keyword(s):  
Dna Binding ◽  
Transcription Start Site ◽  
Promoter Region ◽  
Binding Activity ◽  
Shigella Sonnei ◽  
Virulence Plasmid ◽  
Start Site ◽  
Transcription Start ◽  
Dna Binding Activity ◽  
K 12

ABSTRACT The InvE protein positively regulates the expression of virulence genes ipaBCD in Shigella sonnei. The InvE has significant homology with ParB of plasmid P1, which is known as a plasmid partitioning factor with DNA binding ability. Although the DNA binding activity of InvE has been predicted, it is not known whether the DNA binding activity is necessary for type III secretion system-associated gene expression. In this study, we determined the transcription start site of the icsB-ipaBCD operon (ipa operon) and constructed a series of deletions of the icsB promoter region in the Escherichia coli K-12 background. The deletion study revealed that an 86-bp region upstream of the icsB transcription start site was essential for expression of the ipa operon, where the ParB binding motif (ParB BoxA-like sequence) was observed. Purified glutathione S-transferase-InvE fusion protein bound directly to the −93 to −54 region (designating the icsB transcription start site as nucleotide +1) containing the ParB BoxA-like sequence. These results indicated that InvE bound directly to the promoter region.

scholarly journals Transcription Regulation by Tandem-Bound FNR at Escherichia coli Promoters

2003 ◽  
Vol 185 (20) ◽  
pp. 5993-6004 ◽  
Author(s):  
Anne M. L. Barnard ◽  
Jeffrey Green ◽  
Stephen J. W. Busby
Keyword(s):  
Escherichia Coli ◽  
Transcription Factor ◽  
Binding Site ◽  
Transcription Regulation ◽  
Transcription Start Site ◽  
Promoter Activity ◽  
Start Site ◽  
Transcription Start ◽  
Substitution Mutant

ABSTRACT FNR is an Escherichia coli transcription factor that regulates the transcription of many genes in response to anaerobiosis. We have constructed a series of artificial FNR-dependent promoters, based on the melR promoter, in which a consensus FNR binding site was centered at position −41.5 relative to the transcription start site. A second consensus FNR binding site was introduced at different upstream locations, and promoter activity was assayed in vivo. FNR can activate transcription from these promoters when the upstream FNR binding site is located at many different positions. However, sharp repression is observed when the upstream-bound FNR is located near positions −85 or −95. This repression is relieved by the FNR G74C substitution mutant, previously identified as being defective in transcription repression at the yfiD promoter. A parallel series of artificial FNR-dependent promoters, carrying a consensus FNR binding site at position −61.5 and a second upstream DNA site for FNR, was also constructed. Again, promoter activity was repressed by FNR when the upstream-bound FNR was located at particular positions.

scholarly journals Lysine Represses Transcription of the Escherichia coli dapB Gene by Preventing Its Activation by the ArgP Activator

2008 ◽  
Vol 190 (15) ◽  
pp. 5224-5229 ◽  
Author(s):  
Jean Bouvier ◽  
Patrick Stragier ◽  
Violette Morales ◽  
Elisabeth Rémy ◽  
Claude Gutierrez
Keyword(s):  
Escherichia Coli ◽  
Transcription Start Site ◽  
Biosynthetic Pathway ◽  
Genomic Library ◽  
Regulatory Region ◽  
Null Mutation ◽  
Start Site ◽  
Transcription Start ◽  
Gene Encoding ◽  
Gel Retardation Assay

ABSTRACT The Escherichia coli dapB gene encodes one of the enzymes of the biosynthetic pathway leading to lysine and its immediate precursor, diaminopimelate. Expression of dapB is repressed by lysine, but no trans-acting regulator has been identified so far. Our analysis of the dapB regulatory region shows that sequences located in the −81/−118 interval upstream of the transcription start site are essential for full expression of dapB, as well as for lysine repression. Screening a genomic library for a gene that could alleviate lysine repression when present in multicopy led to the recovery of argP, a gene encoding an activating protein of the LysR-type family, known to use lysine as an effector. An argP null mutation strongly decreases dapB transcription that becomes insensitive to lysine. Purified His6-tagged ArgP protein binds with an apparent K d of 35 nM to the dapB promoter in a gel retardation assay, provided that sequences up to −103 are present. In the presence of l-lysine and l-arginine, the binding of ArgP to dapB is partly relieved. These results fit with a model in which ArgP contributes to enhanced transcription of dapB when lysine becomes limiting.

scholarly journals The UP Element Is Necessary but Not Sufficient for Growth Rate-Dependent Control of the Escherichia coli guaB Promoter

2008 ◽  
Vol 190 (7) ◽  
pp. 2450-2457 ◽  
Author(s):  
Seyyed I. Husnain ◽  
Mark S. Thomas
Keyword(s):  
Escherichia Coli ◽  
Growth Rate ◽  
Transcription Start Site ◽  
De Novo ◽  
Start Site ◽  
Transcription Start ◽  
Lower Growth ◽  
Α Subunit ◽  
Rate Dependent ◽  
Up Elements

ABSTRACT The Escherichia coli guaB promoter (P guaB ) regulates the transcription of two genes, guaB and guaA, that are required for de novo synthesis of GMP, a precursor for the synthesis of guanine nucleoside triphosphates. The activity of P guaB is subject to growth rate-dependent control (GRDC). Here we show that the A+T-rich sequence located between positions −59 and −38 relative to the guaB transcription start site stimulates transcription from P guaB ∼8- to 10-fold and, in common with other UP elements, requires the C-terminal domain of the RNA polymerase α subunit for activity. Like the rrnB P1 UP element, the P guaB UP element contains two independently acting subsites located at positions −59 to −47 and −46 to −38 and can stimulate transcription when placed upstream of the lacP1 promoter. We reveal a novel role for the P guaB UP element by demonstrating that it is required for GRDC. The involvement of the UP element in GRDC also requires the participation of sequences located at least 100 bp upstream of the guaB transcription start site. These sequences are required for down-regulation of P guaB activity at lower growth rates.

scholarly journals Preferential Reduction of the Thermodynamically Less Favorable Electron Acceptor, Sulfate, by a Nitrate-Reducing Strain of the Sulfate-Reducing Bacterium Desulfovibrio desulfuricans 27774

2008 ◽  
Vol 191 (3) ◽  
pp. 882-889 ◽  
Author(s):  
Angeliki Marietou ◽  
Lesley Griffiths ◽  
Jeff Cole
Keyword(s):  
Transcription Start Site ◽  
Electron Acceptor ◽  
Nitrate Reduction ◽  
Desulfovibrio Desulfuricans ◽  
Start Codon ◽  
Start Site ◽  
Transcription Start ◽  
Sulfate Reducing ◽  
Reverse Transcription Pcr ◽  
Nitrate Induction

ABSTRACT Desulfovibrio desulfuricans strain 27774 is one of a relative small group of sulfate-reducing bacteria that can also grow with nitrate as an alternative electron acceptor, but how nitrate reduction is regulated in any sulfate-reducing bacterium is controversial. Strain 27774 grew more rapidly and to higher yields of biomass with nitrate than with sulfate or nitrite as the only electron acceptor. In the presence of both sulfate and nitrate, sulfate was used preferentially, even when cultures were continuously gassed with nitrogen and carbon dioxide to prevent sulfide inhibition of nitrate reduction. The napC transcription start site was identified 112 bases upstream of the first base of the translation start codon. Transcripts initiated at the napC promoter that were extended across the napM-napA boundary were detected by reverse transcription-PCR, confirming that the six nap genes can be cotranscribed as a single operon. Real-time PCR experiments confirmed that nap operon expression is regulated at the level of mRNA transcription by at least two mechanisms: nitrate induction and sulfate repression. We speculate that three almost perfect inverted-repeat sequences located upstream of the transcription start site might be binding sites for one or more proteins of the CRP/FNR family of transcription factors that mediate nitrate induction and sulfate repression of nitrate reduction by D. desulfuricans.

scholarly journals Genetic Features of MCR-1-Producing Colistin-Resistant Escherichia coli Isolates in South Africa

2016 ◽  
Vol 60 (7) ◽  
pp. 4394-4397 ◽  
Author(s):  
Laurent Poirel ◽  
Nicolas Kieffer ◽  
Adrian Brink ◽  
Jennifer Coetze ◽  
Aurélie Jayol ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
South Africa ◽  
Transcription Start Site ◽  
Dna Sequences ◽  
Start Site ◽  
Transcription Start ◽  
Content Type ◽  
Promoter Sequences ◽  
Genetic Features ◽  
Community Patients

ABSTRACTA series of colistin-resistantEscherichia coliclinical isolates was recovered from hospitalized and community patients in South Africa. Seven clonally unrelated isolates harbored themcr-1gene located on different plasmid backbones. Two distinct plasmids were fully sequenced, and identical 2,600-bp-long DNA sequences defining amcr-1cassette were identified. Promoter sequences responsible for the expression ofmcr-1, deduced from the precise identification of the +1 transcription start site formcr-1, were characterized.

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