Members of the piggyBac superfamily of DNA transposons are widely distributed in host genomes ranging from insects to mammals. The human genome has retained five piggyBac-derived genes as domesticated elements although they are no longer mobile. Here, we have investigated the transposition properties of piggyBat from Myotis lucifugus, the only known active mammalian DNA transposon, and show that its low activity in human cells is due to subterminal inhibitory DNA sequences.
View Article and Find Full Text PDFBacterial plant pathogens adjust their gene expression programs in response to environmental signals and host-derived compounds. This ensures that virulence genes or genes encoding proteins, which promote bacterial fitness in a host environment, are expressed only when needed. Such regulation is in the purview of transcription factors, many of which belong to the ubiquitous multiple antibiotic resistance regulator (MarR) protein family.
View Article and Find Full Text PDFUnder stress conditions, ribosome biogenesis is downregulated. This process requires that expression of ribosomal RNA, ribosomal protein, and ribosome biogenesis genes be controlled in a coordinated fashion. The mechanistic Target of Rapamycin Complex 1 (mTORC1) participates in sensing unfavorable conditions to effect the requisite change in gene expression.
View Article and Find Full Text PDFThe rising threat of antibiotic resistance in pathogenic bacteria emphasizes the need for new therapeutic strategies. This review focuses on bacterial transcription factors (TFs), which play crucial roles in bacterial pathogenesis. We discuss the regulatory roles of these factors through examples, and we outline potential therapeutic strategies targeting bacterial TFs.
View Article and Find Full Text PDFBacterial panicle blight is caused by Burkholderia glumae and results in damage to rice crops worldwide. Virulence of B. glumae requires quorum sensing (QS)-dependent synthesis and export of toxoflavin, responsible for much of the damage to rice.
View Article and Find Full Text PDFThe transcriptional regulator PecS is encoded by select bacterial pathogens. For instance, in the plant pathogen Dickeya dadantii, PecS controls a range of virulence genes, including pectinase genes and the divergently oriented gene , which encodes an efflux pump through which the antioxidant indigoidine is exported. In the plant pathogen (formerly named Agrobacterium tumefaciens), the locus is conserved.
View Article and Find Full Text PDFBurkholderia thailandensis is a member of the Burkholderia pseudomallei complex. It encodes the transcription factor MftR, which is conserved among the more pathogenic spp. and previously shown to be a global regulator of gene expression.
View Article and Find Full Text PDFBacteria respond to changing environments by modulating their gene expression programs. One of the mechanisms by which this may be accomplished is by substituting the primary σ factor with an alternative σ factor belonging to the family of extracytoplasmic function (ECF) σ factors. ECF σ factors are activated only in presence of specific signals, and they direct the RNA polymerase (RNAP) to transcribe a defined subset of genes.
View Article and Find Full Text PDFRibosome biogenesis is an energetically costly process, and tight regulation is required for stoichiometric balance between components. This requires coordination of RNA polymerases I, II, and III. Lack of nutrients or the presence of stress leads to downregulation of ribosome biogenesis, a process for which mechanistic target of rapamycin complex I (mTORC1) is key.
View Article and Find Full Text PDFAppl Environ Microbiol
November 2021
In this study, comprehensive analyses were performed to determine the function of an atypical MarR homolog in sp. strain As-55. Genomic analyses of sp.
View Article and Find Full Text PDFlaboratory strains remain instrumental for the development of tools and techniques in molecular microbiology. The transcriptional regulator SlyA, associated with host-derived oxidative stress, antibiotic resistance, and virulence, is prominent in Here, we announce a transcriptome data set detailing the global gene expression in BW25113 and its mutant.
View Article and Find Full Text PDFThe stringent response involves accumulation of (p)ppGpp, and it ensures that survival is prioritized. Production of (p)ppGpp requires purine synthesis, and upregulation of an operon that encodes the purine salvage enzyme xanthine dehydrogenase (Xdh) has been observed during stringent response in some bacterial species, where direct binding of ppGpp to a TetR-family transcription factor is responsible for increased xdh gene expression. We show here that the plant pathogen Ralstonia solanacearum has a regulatory system in which the LysR-family transcription factor XanR controls expression of the xan operon; this operon encodes Xdh as well as other enzymes involved in purine salvage, which favor accumulation of xanthine.
View Article and Find Full Text PDFAntibiotics (Basel)
September 2019
The emergence of multiple antibiotic resistant bacteria has pushed the available pool of antibiotics to the brink. Bacterial secondary metabolites have long been a valuable resource in the development of antibiotics, and the genus has recently emerged as a source of novel compounds with antibacterial, antifungal, and anti-cancer activities. Genome mining has contributed to the identification of biosynthetic gene clusters, which encode enzymes that are responsible for synthesis of such secondary metabolites.
View Article and Find Full Text PDFStress and starvation causes bacterial cells to activate the stringent response. This results in down-regulation of energy-requiring processes related to growth, as well as an upregulation of genes associated with survival and stress responses. Guanosine tetra- and pentaphosphates (collectively referred to as (p)ppGpp) are critical for this process.
View Article and Find Full Text PDFThe plant pathogen Pectobacterium atrosepticum encounters a stressful environment when it colonizes the plant apoplast. Chief among the stressors are the reactive oxygen species (ROS) that are produced by the host as a first line of defense. Bacterial transcription factors in turn use these signals as cues to upregulate expression of virulence-associated genes.
View Article and Find Full Text PDFThe genus Vibrio includes serious human pathogens, and mollusks are a significant reservoir for species such as V. vulnificus. Vibrio species encode PecS, a member of the multiple antibiotic resistance regulator (MarR) family of transcription factors; pecS is divergently oriented to pecM, which encodes an efflux pump.
View Article and Find Full Text PDFThe antibiotic trimethoprim is frequently used to manage infections, and members of the resistance-nodulation-division (RND) family of efflux pumps have been implicated in multidrug resistance of this species complex. We show here that a member of the distinct multidrug resistance B (EmrB) family is a primary exporter of trimethoprim in , as evidenced by increased trimethoprim sensitivity after inactivation of , the gene that encodes EmrB. We also found that the gene is up-regulated following the addition of gentamicin and that this up-regulation is due to repression of the gene encoding OstR, a member of the multiple antibiotic resistance regulator (MarR) family.
View Article and Find Full Text PDFSpecies within the genus exhibit remarkable phenotypic diversity. Genomic plasticity, including genome reduction and horizontal gene transfer, has been correlated with virulence traits in several species. However, the conservation of virulence genes in species otherwise considered to have limited potential for infection suggests that phenotypic diversity may not be explained solely on the basis of genetic diversity.
View Article and Find Full Text PDFMany bacteria encode biosynthetic proteins that produce a vast array of natural products. These compounds are often synthesized during host invasion as they function as virulence factors. In addition, such secondary metabolites have yielded numerous molecular scaffolds with pharmaceutical and clinical importance.
View Article and Find Full Text PDFAgrobacterium fabrum induces tumor growth in susceptible plant species. The upregulation of virulence genes that occurs when the bacterium senses plant-derived compounds is enhanced by acidic pH and limiting inorganic phosphate. Nutrient starvation may also trigger the stringent response, and purine salvage is among the pathways expected to be favored under such conditions.
View Article and Find Full Text PDFCurr Genet
February 2018
Under conditions of nutrient limitation and cellular stress, or by addition of rapamycin, the mechanistic target of rapamycin complex 1 (mTORC1) is inhibited. This results in downregulation of genes that encode rRNA and ribosomal proteins. While most of the mTORC1 functions that have been previously characterized at a mechanistic level take place in the cytoplasm, nuclear roles have also been reported, including direct association of TOR kinase with rRNA genes.
View Article and Find Full Text PDFCationic ionic liquids-based surfactants (ILS), such as 4-methyl pyridinium bromide (CPBr, where n=4,6,8), were used in preparation of polyacrylamide gels, sample buffer, and running buffer for cationic ILS polyacrylamide gel electrophoresis (ILS-PAGE). These ILS are liquids in the pure state and were selected for improved separation of ribonuclease b (Rib b) glycoforms in a single step and a protein mixture containing bovine serum albumin (BSA, pI-4.8, 66.
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