Abstract:
:Genes acrAB encode a multidrug efflux pump in Escherichia coli. We have previously reported that transcription of acrAB is increased under general stress conditions (i.e. 4% ethanol, 0.5 M NaCl, and the stationary phase in Luria-Bertani medium). In this study, lacZ transcriptional fusions and an in vitro gel mobility shift assay have been utilized to study the mechanisms governing the regulation of acrAB. We found that a closely linked gene, acrR, encoded a repressor of acrAB. Nevertheless, the general stress conditions increased transcription of acrAB in the absence of functional AcrR, and such conditions surprisingly increased the transcription of acrR even more strongly than that of acrAB. These results suggest that the general-stress-induced transcription of acrAB is primarily mediated by global regulatory pathway(s), and that one major role of AcrR is to function as a specific secondary modulator to fine tune the level of acrAB transcription and to prevent the unwanted overexpression of acrAB. To our knowledge, this represents a novel mechanism of regulating gene expression in E. coli. Evidence also suggests that the up-regulation of acrAB expression under general stress conditions is not likely to be mediated by the known global regulators, such as MarA or SoxS, although elevated levels of these proteins were shown to increase the transcription of acrAB.
journal_name
Mol Microbioljournal_title
Molecular microbiologyauthors
Ma D,Alberti M,Lynch C,Nikaido H,Hearst JEdoi
10.1046/j.1365-2958.1996.357881.xsubject
Has Abstractpub_date
1996-01-01 00:00:00pages
101-12issue
1eissn
0950-382Xissn
1365-2958journal_volume
19pub_type
杂志文章abstract::Several bacterial genera express proteins that contain collagen-like regions, which are associated with variable (V) non-collagenous regions. The streptococcal collagen-like proteins, Scl1 and Scl2, of group A Streptococcus (GAS) are members of this 'prokaryotic collagen' family, and they too contain an amino-terminal...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/j.1365-2958.2006.05237.x
更新日期:2006-07-01 00:00:00
abstract::Folate metabolism in malaria parasites is a long-standing, clinical target for chemotherapy and prophylaxis. However, despite determination of the complete genome sequence of the lethal species Plasmodium falciparum, the pathway of de novo folate biosynthesis remains incomplete, as no candidate gene for dihydroneopter...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/j.1365-2958.2007.06073.x
更新日期:2008-02-01 00:00:00
abstract::We have characterized a series of amber mutations in the A gene of bacteriophage Mu encoding the phage transposase. We tested different activities of these mutant proteins either in a sup0 strain or in different sup bacteria. In conjunction with the results described in the accompanying paper by Bétermier et al. (1989...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/j.1365-2958.1989.tb00265.x
更新日期:1989-09-01 00:00:00
abstract::In this report we evaluate the role of catalase in the survival of Bordetella pertussis within human polymorphonuclear leukocytes (PMNs). Crude extracts of B. pertussis exhibited a single catalase activity when subjected to non-denaturing polyacrylamide gel electrophoresis and assayed for catalase activity. A plasmid ...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/j.1365-2958.1994.tb01272.x
更新日期:1994-10-01 00:00:00
abstract::The important human pathogen Streptococcus pyogenes (the group A streptococcus or GAS) causes diseases ranging from mild, self-limiting pharyngitis to severe invasive infections. Regulation of the expression of GAS genes in response to specific environmental differences within the host is probably key in determining t...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1046/j.1365-2958.2001.02657.x
更新日期:2001-10-01 00:00:00
abstract::To identify Rhodobacter capsulatus nif genes necessary for the alternative nitrogenase, strains carrying defined mutations in 32 genes and open reading frames of nif region A, B or C were constructed. The ability of these mutants to grow on nitrogen-free medium with molybdenum (Nif phenotype) or in a nifHDK deletion b...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/j.1365-2958.1993.tb01611.x
更新日期:1993-05-01 00:00:00
abstract::We studied the molecular mechanism of neuronal calcium sensor-1 (NCS-1) signaling pathway for tolerance to Ca2+ stress in Neurospora crassa. Increasing concentration of Ca2+ increased the expression of ncs-1; however, the calcineurin inhibitor FK506 severely reduced ncs-1 mRNA transcript levels. Chromatin immunoprecip...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/mmi.14234
更新日期:2019-06-01 00:00:00
abstract::The proton-driven flagellar motor of Salmonella enterica can accommodate a dozen MotA/B stators in a load-dependent manner. The C-terminal periplasmic domain of MotB acts as a structural switch to regulate the number of active stators in the motor in response to load change. The cytoplasmic loop termed MotAC is respon...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/mmi.13843
更新日期:2017-11-01 00:00:00
abstract::The tetA(L) gene of Bacillus subtilis encodes a transmembrane protein that can function as a Tc-metal/H+ antiporter, conferring low-level resistance to tetracycline. The TetA(L) coding sequence is preceded by a leader region that contains a 20-amino-acid open reading frame and an appropriately spaced ribosome binding ...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1046/j.1365-2958.1998.01119.x
更新日期:1998-12-01 00:00:00
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journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/j.1365-2958.1992.tb00859.x
更新日期:1992-05-01 00:00:00
abstract::Biofilm formation is a social behaviour that generates favourable conditions for sustained survival in the natural environment. For the Gram-positive bacterium Bacillus subtilis the process involves the differentiation of cell fate within an isogenic population and the production of communal goods that form the biofil...
journal_title:Molecular microbiology
pub_type: 杂志文章,评审
doi:10.1111/mmi.12697
更新日期:2014-08-01 00:00:00
abstract::Emerging lipidomic technologies have enabled researchers to dissect the complex roles of phospholipases in lipid metabolism, cellular signaling and immune regulation. Host phospholipase products are involved in stimulating and resolving the inflammatory response to pathogens. While many pathogen-derived phospholipases...
journal_title:Molecular microbiology
pub_type: 杂志文章,评审
doi:10.1111/mmi.13871
更新日期:2018-01-01 00:00:00
abstract::The location of FtsQ, an Escherichia coli protein essential for cell division, is, under physiological conditions, in the cytoplasmic membrane facing towards the periplasmic space. An amino-proximal hydrophobic domain is required for FtsQ to reach its location and for its activity in the cell. Overexpression of modifi...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/j.1365-2958.1992.tb01520.x
更新日期:1992-03-01 00:00:00
abstract::The flow of information from the outside to the inside of bacterial cells is largely directed by protein kinases. In addition to histidine/aspartate phosphorelays of two-component response regulators, recent work in Mycobacterium tuberculosis (Mtb) reinforces the idea that phosphorylation on serine (Ser), threonine (T...
journal_title:Molecular microbiology
pub_type: 杂志文章,评审
doi:10.1111/mmi.12747
更新日期:2014-10-01 00:00:00
abstract::The Escherichia coli toxin exporter HlyB comprises an integral membrane domain fused to a cytoplasmic domain of the ATP-binding cassette (ABC) super-family, and it directs translocation of the 110kDa haemolysin protein out of the bacterial cell without using an N-terminal secretion signal peptide. We have exploited th...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/j.1365-2958.1995.tb02394.x
更新日期:1995-04-01 00:00:00
abstract::In spite of displaying the most extreme dormancy and resistance properties known among living systems, bacterial endospores retain an alert environment-sensing mechanism that can respond within seconds to the presence of specific germinants. This germination response is triggered in the absence of both germinant and g...
journal_title:Molecular microbiology
pub_type: 杂志文章,评审
doi:10.1111/j.1365-2958.1990.tb02023.x
更新日期:1990-01-01 00:00:00
abstract::Metal ions are crucial trace elements for bacteria infecting the human host. The LraI (lipoprotein receptor-associated antigen I) transporter in Streptococcus spp. belongs to the superfamily of ABC transporters. The transporter consists of a lipoprotein, an ATP-binding protein and a hydrophobic integral membrane prote...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1046/j.1365-2958.1999.01626.x
更新日期:1999-11-01 00:00:00
abstract::The surface-located fibrinogen-binding protein (clumping factor; ClfA) of Staphylococcus aureus has an unusual dipeptide repeat linking the ligand binding domain to the wall-anchored region. Southern blotting experiments revealed several other loci in the S. aureus Newman genome that hybridized to a probe comprising D...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1046/j.1365-2958.1998.01050.x
更新日期:1998-10-01 00:00:00
abstract::CoiA is a transient protein expressed specifically during competence and required for genetic transformation in Streptococcus pneumoniae, but not for DNA uptake. It is widely conserved among Gram-positive bacteria but its function is unknown. Here we report that although the rate of DNA uptake was not affected in a co...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/j.1365-2958.2006.05558.x
更新日期:2007-02-01 00:00:00
abstract::When fungi grow on plant or insect surfaces coated with wax polyesters that protect against pathogens, the fungi generally form aerial hyphae to contact the surfaces. Aerial structures such as hyphae and conidiophores are coated with hydrophobins, which are surface-active proteins involved in adhesion to hydrophobic s...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/j.1365-2958.2005.04803.x
更新日期:2005-09-01 00:00:00
abstract::Listeria monocytogenes is a facultative intracellular pathogen which secretes a pore-forming cytolysin, listeriolysin O (LLO), necessary for intracellular growth. Clostridium perfringens is an extracellular pathogen which secretes a related cytolysin, perfringolysin O (PFO). When PFO is secreted by intracellular L. mo...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1046/j.1365-2958.1996.00074.x
更新日期:1996-09-01 00:00:00
abstract::Infections with the azole-refractory yeast Candida glabrata are now commonly treated with the echinocandins caspofungin (CSF) or micafungin (MCF). True resistance (> 32-fold decreased susceptibility) to these lipopeptide inhibitors of cell wall synthesis is rare and strictly associated with mutations in integral memb...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/j.1365-2958.2012.08194.x
更新日期:2012-10-01 00:00:00
abstract::We have shown previously that some particular mutations in bacteriophage Mu repressor, the frameshift vir mutations, made the protein very sensitive to the Escherichia coli ATP-dependent Clp protease. This enzyme is formed by the association between a protease subunit (ClpP) and an ATPase subunit. ClpA, the best chara...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/j.1365-2958.1994.tb00387.x
更新日期:1994-03-01 00:00:00
abstract::The ability of a bacterial pathogen to monitor available carbon sources in host tissues provides a clear fitness advantage. In the group A streptococcus (GAS), the virulence regulator Mga contains homology to phosphotransferase system (PTS) regulatory domains (PRDs) found in sugar operon regulators. Here we show that ...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/mmi.12250
更新日期:2013-06-01 00:00:00
abstract::Myxococcus xanthus is a Gram-negative, soil-dwelling bacterium with a complex life cycle which includes fruiting body formation and sporulation in response to starvation. This developmental process is slow, requiring a minimum of 24-48 h, and requires cells to be at high cell density on a solid surface. It is known th...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1046/j.1365-2958.1997.3931757.x
更新日期:1997-05-01 00:00:00
abstract::The enteric gamma-proteobacterium Photorhabdus luminescens kills a wide range of insects, whilst also maintaining a mutualistic relationship with soil nematodes from the family Heterorhabditis. Pathogenicity is associated with bacterial exponential growth, whilst mutualism is associated with post-exponential (stationa...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/mmi.13345
更新日期:2016-05-01 00:00:00
abstract::Histidine kinases (HK) sense and transduce via phosphorylation events many intra- and extracellular signals in bacteria, archaea, slime moulds and plants. HK are also widespread in the fungal kingdom, but their precise roles in the regulation of physiological processes remain largely obscure. Expanding genomic resourc...
journal_title:Molecular microbiology
pub_type: 杂志文章,评审
doi:10.1111/mmi.12911
更新日期:2015-03-01 00:00:00
abstract::In the yeast Saccharomyces cerevisiae, PKA and Sch9 exert similar physiological roles in response to nutrient availability. However, their functional redundancy complicates to distinguish properly the target genes for both kinases. In this article, we analysed different phenotypic read-outs. The data unequivocally sho...
journal_title:Molecular microbiology
pub_type: 杂志文章
doi:10.1111/j.1365-2958.2004.04429.x
更新日期:2005-02-01 00:00:00
abstract::Small regulatory RNAs (sRNAs) are well known to command bacterial protein synthesis by modulating the translation and decay of target mRNAs. Most sRNAs are specifically regulated by a cognate transcription factor under certain growth or stress conditions. Investigations of the conserved Hfq-dependent MicM sRNA in Esch...
journal_title:Molecular microbiology
pub_type: 评论,杂志文章
doi:10.1111/j.1365-2958.2009.06806.x
更新日期:2009-09-01 00:00:00
abstract::The group A streptococcus (GAS) causes a variety of human diseases, including toxic shock syndrome and necrotizing fasciitis, which are both associated with significant mortality. Even the superficial self-limiting diseases caused by GAS, such as pharyngitis, impose a significant economic burden on society. GAS can ca...
journal_title:Molecular microbiology
pub_type: 杂志文章,评审
doi:10.1111/j.1365-2958.2007.05649.x
更新日期:2007-04-01 00:00:00