scholarly journals Genome-Wide Identification of Francisella tularensis Virulence Determinants

2007 ◽  
Vol 75 (6) ◽  
pp. 3089-3101 ◽  
Author(s):  
Jingliang Su ◽  
Jun Yang ◽  
Daimin Zhao ◽  
Thomas H. Kawula ◽  
Jeffrey A. Banas ◽  
...  
Keyword(s):  
Francisella Tularensis ◽  
Stress Responses ◽  
Small Subset ◽  
Virulence Determinants ◽  
Genome Wide ◽  
Genes Encoding ◽  
Capsule Locus ◽  
Life Threatening ◽  
Transposon Mutants ◽  
Schu S4

ABSTRACT Francisella tularensis is a gram-negative pathogen that causes life-threatening infections in humans and has potential for use as a biological weapon. The genetic basis of the F. tularensis virulence is poorly understood. This study screened a total of 3,936 transposon mutants of the live vaccine strain for infection in a mouse model of respiratory tularemia by signature-tagged mutagenesis. We identified 341 mutants attenuated for infection in the lungs. The transposon disruptions were mapped to 95 different genes, virtually all of which are also present in the genomes of other F. tularensis strains, including human pathogenic F. tularensis strain Schu S4. A small subset of these attenuated mutants carried insertions in the genes encoding previously known virulence factors, but the majority of the identified genes have not been previously linked to F. tularensis virulence. Among these are genes encoding putative membrane proteins, proteins associated with stress responses, metabolic proteins, transporter proteins, and proteins with unknown functions. Several attenuated mutants contained disruptions in a putative capsule locus which partially resembles the poly-γ-glutamate capsule biosynthesis locus of Bacillus anthracis, the anthrax agent. Deletional mutation analysis confirmed that this locus is essential for F. tularensis virulence.

scholarly journals Elucidating the regulatory mechanism of Swi1 prion in global transcription and stress responses

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Zhiqiang Du ◽  
Jeniece Regan ◽  
Elizabeth Bartom ◽  
Wei-Sheng Wu ◽  
Li Zhang ◽  
...  
Keyword(s):  
Stress Responses ◽  
Regulation Of Transcription ◽  
Interacting Proteins ◽  
Environmental Stress Response ◽  
Key Factors ◽  
Cellular Functions ◽  
Beneficial Effects ◽  
Genome Wide ◽  
Genes Encoding ◽  
A Subunit

AbstractTranscriptional regulators are prevalent among identified prions in Saccharomyces cerevisiae, however, it is unclear how prions affect genome-wide transcription. We show here that the prion ([SWI+]) and mutant (swi1∆) forms of Swi1, a subunit of the SWI/SNF chromatin-remodeling complex, confer dramatically distinct transcriptomic profiles. In [SWI+] cells, genes encoding for 34 transcription factors (TFs) and 24 Swi1-interacting proteins can undergo transcriptional modifications. Several TFs show enhanced aggregation in [SWI+] cells. Further analyses suggest that such alterations are key factors in specifying the transcriptomic signatures of [SWI+] cells. Interestingly, swi1∆ and [SWI+] impose distinct and oftentimes opposite effects on cellular functions. Translation-associated activities, in particular, are significantly reduced in swi1∆ cells. Although both swi1∆ and [SWI+] cells are similarly sensitive to thermal, osmotic and drought stresses, harmful, neutral or beneficial effects were observed for a panel of tested chemical stressors. Further analyses suggest that the environmental stress response (ESR) is mechanistically different between swi1∆ and [SWI+] cells—stress-inducible ESR (iESR) are repressed by [SWI+] but unchanged by swi1∆ while stress-repressible ESR (rESR) are induced by [SWI+] but repressed by swi1∆. Our work thus demonstrates primarily gain-of-function outcomes through transcriptomic modifications by [SWI+] and highlights a prion-mediated regulation of transcription and phenotypes in yeast.

scholarly journals Genome-wide analyses of genes encoding FK506-binding proteins reveal their involvement in abiotic stress responses in apple

BMC Genomics ◽  
2018 ◽  
Vol 19 (1) ◽  
Author(s):  
Qinglong Dong ◽  
Ke Mao ◽  
Dingyue Duan ◽  
Shuang Zhao ◽  
Yanpeng Wang ◽  
...  
Keyword(s):  
Abiotic Stress ◽  
Stress Responses ◽  
Binding Proteins ◽  
Genome Wide ◽  
Genes Encoding ◽  
Fk506 Binding Proteins

Genome-wide analysis of genes encoding MBD domain-containing proteins from tomato suggest their role in fruit development and abiotic stress responses

2018 ◽  
Vol 45 (6) ◽  
pp. 2653-2669 ◽  
Author(s):  
Adwaita Prasad Parida ◽  
Utkarsh Raghuvanshi ◽  
Amit Pareek ◽  
Vijendra Singh ◽  
Rahul Kumar ◽  
...  
Keyword(s):  
Abiotic Stress ◽  
Stress Responses ◽  
Fruit Development ◽  
Genome Wide Analysis ◽  
Genome Wide ◽  
Genes Encoding

scholarly journals Disruption of Francisella tularensis Schu S4iglI,iglJ, andpdpCGenes Results in Attenuation for Growth in Human Macrophages andIn VivoVirulence in Mice and Reveals a Unique Phenotype forpdpC

2012 ◽  
Vol 81 (3) ◽  
pp. 850-861 ◽  
Author(s):  
Matthew E. Long ◽  
Stephen R. Lindemann ◽  
Jed A. Rasmussen ◽  
Bradley D. Jones ◽  
Lee-Ann H. Allen
Keyword(s):  
Francisella Tularensis ◽  
Bacterial Pathogen ◽  
Human Monocyte ◽  
Pathogenicity Island ◽  
Intermediate Phenotype ◽  
Small Subset ◽  
Content Type ◽  
Isolation And Characterization ◽  
Schu S4

ABSTRACTFrancisella tularensisis a facultative intracellular bacterial pathogen and the causative agent of tularemia. After infection of macrophages, the organism escapes from its phagosome and replicates to high density in the cytosol, but the bacterial factors required for these aspects of virulence are incompletely defined. Here, we describe the isolation and characterization ofFrancisella tularensissubsp.tularensisstrain Schu S4 mutants that lack functionaliglI,iglJ, orpdpC, three genes of theFrancisellapathogenicity island. Our data demonstrate that these mutants were defective for replication in primary human monocyte-derived macrophages and murine J774 cells yet exhibited two distinct phenotypes. TheiglIandiglJmutants were similar to one another, exhibited profound defects in phagosome escape and intracellular growth, and appeared to be trapped in cathepsin D-positive phagolysosomes. Conversely, thepdpCmutant avoided trafficking to lysosomes, phagosome escape was diminished but not ablated, and these organisms replicated in a small subset of infected macrophages. The phenotype of each mutant strain was reversed bytranscomplementation.In vivovirulence was assessed by intranasal infection of BALB/c mice. The mutants appeared avirulent, as all mice survived infection with 108CFUiglJ-orpdpC-deficient bacteria. Nevertheless, thepdpCmutant disseminated to the liver and spleen before being eliminated, whereas theiglJmutant did not. Taken together, our data demonstrate that the pathogenicity island genes tested are essential forF. tularensisSchu S4 virulence and further suggest thatpdpCmay play a unique role in this process, as indicated by its distinct intermediate phenotype.

scholarly journals Identification of Mechanisms for Attenuation of the FSC043 Mutant of Francisella tularensis SCHU S4

2014 ◽  
Vol 82 (9) ◽  
pp. 3622-3635 ◽  
Author(s):  
Marie Lindgren ◽  
Linda Tancred ◽  
Igor Golovliov ◽  
Wayne Conlan ◽  
Susan M. Twine ◽  
...  
Keyword(s):  
Francisella Tularensis ◽  
Virulent Strain ◽  
Small Subset ◽  
Intracellular Replication ◽  
Content Type ◽  
Infected Cells ◽  
Essential Contribution ◽  
Respiratory Challenge ◽  
Schu S4 ◽  
Highly Virulent

ABSTRACTPreviously, we identified a spontaneous, essentially avirulent mutant, FSC043, of the highly virulent strain SCHU S4 ofFrancisella tularensissubsp.tularensis. We have now characterized the phenotype of the mutant and the mechanisms of its attenuation in more detail. Genetic and proteomic analyses revealed that thepdpEgene and most of thepdpCgene were very markedly downregulated and, as previously demonstrated, that the strain expressed partially deleted and fusedfupAandfupBgenes. FSC043 showed minimal intracellular replication and induced no cell cytotoxicity. The mutant showed delayed phagosomal escape; at 18 h, colocalization with LAMP-1 was 80%, indicating phagosomal localization, whereas the corresponding percentages for SCHU S4 and the ΔfupAmutant were <10%. However, a small subset of the FSC043-infected cells contained up to 100 bacteria with LAMP-1 colocalization of around 30%. The unusual intracellular phenotype was similar to that of the ΔpdpCand ΔpdpCΔpdpEmutants. Complementation of FSC043 with the intactfupAandfupBgenes did not affect the phenotype, whereas complementation with thepdpCandpdpEgenes restored intracellular replication and led to marked virulence. Even higher virulence was observed after complementation with both double-gene constructs. After immunization with the FSC043 strain, moderate protection against respiratory challenge with the SCHU S4 strain was observed. In summary, FSC043 showed a highly unusual intracellular phenotype, and based on our findings, we hypothesize that the mutation in thepdpCgene makes an essential contribution to the phenotype.

scholarly journals Attenuated Francisella novicida Transposon Mutants Protect Mice against Wild-Type Challenge

2006 ◽  
Vol 74 (9) ◽  
pp. 5095-5105 ◽  
Author(s):  
Rebecca Tempel ◽  
Xin-He Lai ◽  
Lidia Crosa ◽  
Briana Kozlowicz ◽  
Fred Heffron
Keyword(s):  
Bacterial Pathogen ◽  
Host Cells ◽  
Wild Type ◽  
Live Attenuated Vaccine ◽  
Francisella Novicida ◽  
Mouse Macrophages ◽  
Life Threatening ◽  
Transposon Mutants ◽  
High Doses ◽  
Schu S4

ABSTRACT Francisella tularensis is the bacterial pathogen that causes tularemia in humans and a number of animals. To date, there is no approved vaccine for this widespread and life-threatening disease. The goal of this study was to identify F. tularensis mutants that can be used in the development of a live attenuated vaccine. We screened F. novicida transposon mutants to identify mutants that exhibited reduced growth in mouse macrophages, as these cells are the preferred host cells of Francisella and an essential component of the innate immune system. This approach yielded 16 F. novicida mutants that were 100-fold more attenuated for virulence in a mouse model than the wild-type parental strain. These mutants were then tested to determine their abilities to protect mice against challenge with high doses of wild-type bacteria. Five of the 16 attenuated mutants (with mutations corresponding to dsbB, FTT0742, pdpB, fumA, and carB in the F. tularensis SCHU S4 strain) provided mice with protection against challenge with high doses (>8 × 105 CFU) of wild-type F. novicida. We believe that these findings will be of use in the design of a vaccine against tularemia.

scholarly journals Genome-Wide Screen in Francisella novicida for Genes Required for Pulmonary and Systemic Infection in Mice

2008 ◽  
Vol 77 (1) ◽  
pp. 232-244 ◽  
Author(s):  
Petra S. Kraemer ◽  
Allison Mitchell ◽  
Mark R. Pelletier ◽  
Larry A. Gallagher ◽  
Mike Wasnick ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Systemic Infection ◽  
Single Strain ◽  
Francisella Novicida ◽  
Transposon Insertion ◽  
Genome Wide ◽  
Significant Enrichment ◽  
Life Threatening ◽  
Transposon Mutants ◽  
Insertion Mutants

ABSTRACT Francisella tularensis is a gram-negative, highly infectious, aerosolizable facultative intracellular pathogen that causes the potentially life-threatening disease tularemia. To date there is no approved vaccine available, and little is known about the molecular mechanisms important for infection, survival, and dissemination at different times of infection. We report the first whole-genome screen using an inhalation mouse model to monitor infection in the lung and dissemination to the liver and spleen. We queried a comprehensive library of 2,998 sequence-defined transposon insertion mutants in Francisella novicida strain U112 using a microarray-based negative-selection screen. We were able to track the behavior of 1,029 annotated genes, equivalent to a detection rate of 75% and corresponding to ∼57% of the entire F. novicida genome. As expected, most transposon mutants retained the ability to colonize, but 125 candidate virulence genes (12%) could not be detected in at least one of the three organs. They fell into a variety of functional categories, with one-third having no annotated function and a statistically significant enrichment of genes involved in transcription. Based on the observation that behavior during complex pool infections correlated with the degree of attenuation during single-strain infection we identified nine genes expected to strongly contribute to infection. These included two genes, those for ATP synthase C (FTN_1645) and thioredoxin (FTN_1415), that when mutated allowed increased host survival and conferred protection in vaccination experiments.

scholarly journals Roles of Reactive Oxygen Species-Degrading Enzymes of Francisella tularensis SCHU S4

2015 ◽  
Vol 83 (6) ◽  
pp. 2255-2263 ◽  
Author(s):  
Johan Binesse ◽  
Helena Lindgren ◽  
Lena Lindgren ◽  
Wayne Conlan ◽  
Anders Sjöstedt
Keyword(s):  
Reactive Oxygen Species ◽  
Francisella Tularensis ◽  
Reactive Oxygen ◽  
Oxygen Species ◽  
Content Type ◽  
Double Deletion ◽  
Genes Encoding ◽  
J774 Cells ◽  
Schu S4 ◽  
Increased Susceptibility

Francisella tularensisis a facultative intracellular bacterium utilizing macrophages as its primary intracellular habitat and is therefore highly capable of resisting the effects of reactive oxygen species (ROS), potent mediators of the bactericidal activity of macrophages. We investigated the roles of enzymes presumed to be important for protection against ROS. Four mutants of the highly virulent SCHU S4 strain with deletions of the genes encoding catalase (katG), glutathione peroxidase (gpx), a DyP-type peroxidase (FTT0086), or double deletion ofFTT0086andkatGshowed much increased susceptibility to hydrogen peroxide (H2O2) and slightly increased susceptibility to paraquat but not to peroxynitrite (ONOO−) and displayed intact intramacrophage replication. Nevertheless, mice infected with the double deletion mutant showed significantly longer survival than SCHU S4-infected mice. Unlike the aforementioned mutants, deletion of the gene coding for alkyl-hydroperoxide reductase subunit C (ahpC) generated a mutant much more susceptible to paraquat and ONOO−but not to H2O2. It showed intact replication in J774 cells but impaired replication in bone marrow-derived macrophages and in internal organs of mice. The live vaccine strain, LVS, is more susceptible than virulent strains to ROS-mediated killing and possesses a truncated form of FTT0086. Expression of the SCHU S4FTT0086gene rendered LVS more resistant to H2O2, which demonstrates that the SCHU S4 strain possesses additional detoxifying mechanisms. Collectively, the results demonstrate that SCHU S4 ROS-detoxifying enzymes have overlapping functions, and therefore, deletion of one or the other does not critically impair the intracellular replication or virulence, although AhpC appears to have a unique function.

scholarly journals Identification of virulence determinants of Mycobacterium avium that impact on the ability to resist host killing mechanisms

2010 ◽  
Vol 59 (1) ◽  
pp. 8-16 ◽  
Author(s):  
Yong-jun Li ◽  
Lia Danelishvili ◽  
Dirk Wagner ◽  
Mary Petrofsky ◽  
Luiz E. Bermudez
Keyword(s):  
Mycobacterium Avium ◽  
Polyketide Synthase ◽  
Opportunistic Pathogen ◽  
Virulence Determinants ◽  
Genes Encoding ◽  
Transposon Mutants ◽  
Oxidative Products ◽  
Host Killing

Mycobacterium avium is an opportunistic pathogen associated with pulmonary disease in non-AIDS patients and disseminated infection in patients with AIDS. The chief route of infection is by colonization and invasion of the mucosa of the gastrointestinal tract, but infection through the respiratory route also occurs. After crossing the mucosa, M. avium infects and replicates within tissue macrophages. To identify M. avium genes required for survival in vivo, a library of signature-tagged transposon mutants was constructed and screened for clones attenuated in mice. Thirty-two clones were found to be attenuated for their virulence, from which eleven were sequenced and tested further. All the mutants studied grew similarly in vitro to the wild-type MAC104. Ten mutants were tested individually in mice, confirming the attenuated phenotype. MAV_2450, a polyketide synthase homologue to Mycobacterium tuberculosis pks12, was identified. STM5 and STM10 genes (encoding two hypothetical proteins MAV_4292 and MAV_4012) were associated with susceptibility to oxidative products. Mutants MAV_2450, MAV_4292, MAV_0385 and MAV_4264 live in macrophage vacuoles with acidic pH (below 6.9). Mutants MAV_4292, MAV_0385 and MAV_4264 were susceptible to nitric oxide in vitro. The study of individual mutants can potentially lead to new knowledge about M. avium pathogenic mechanisms.

scholarly journals Papain-Like Cysteine Protease Gene Family in Fig (Ficus carica L.): Genome-Wide Analysis and Expression Patterns

2021 ◽  
Vol 12 ◽  
Author(s):  
Yanlei Zhai ◽  
Yuanyuan Cui ◽  
Miaoyu Song ◽  
Alexander Vainstein ◽  
Shangwu Chen ◽  
...  
Keyword(s):  
Stress Responses ◽  
Expression Patterns ◽  
Temperature Response ◽  
Cysteine Proteases ◽  
Ficus Carica ◽  
Protease Gene ◽  
Functional Studies ◽  
Genome Wide ◽  
Genes Encoding ◽  
Localization Analysis

The papain-like cysteine proteases (PLCPs) are the most abundant family of cysteine proteases in plants, with essential roles in biotic/abiotic stress responses, growth and senescence. Papain, bromelain and ficin are widely used in food, medicine and other industries. In this study, 31 PLCP genes (FcPCLPs) were identified in the fig (Ficus carica L.) genome by HMM search and manual screening, and assigned to one of nine subfamilies based on gene structure and conserved motifs. SAG12 and RD21 were the largest subfamilies with 10 and 7 members, respectively. The FcPCLPs ranged from 1,128 to 5,075 bp in length, containing 1–10 introns, and the coding sequence ranged from 624 to 1,518 bp, encoding 207–505 amino acids. Subcellular localization analysis indicated that 24, 2, and 5 PLCP proteins were targeted to the lysosome/vacuole, cytoplasm and extracellular matrix, respectively. Promoter (2,000 bp upstream) analysis of FcPLCPs revealed a high number of plant hormone and low temperature response elements. RNA-seq revealed differential expression of 17 FcPLCPs in the inflorescence and receptacle, and RD21 subfamily members were the major PLCPs expressed in the fruit; 16 and 5 FcPLCPs responded significantly to ethylene and light, respectively. Proteome analyses revealed 18 and 5 PLCPs in the fruit cell soluble proteome and fruit latex, respectively. Ficins were the major PLCP in fig fruit, with decreased abundance in inflorescences, but increased abundance in receptacles of commercial-ripe fruit. FcRD21B/C and FcALP1 were aligned as the genes encoding the main ficin isoforms. Our study provides valuable multi-omics information on the FcPLCP family and lays the foundation for further functional studies.

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