scholarly journals ORF Ι of Mycovirus SsNSRV-1 is Associated with Debilitating Symptoms of Sclerotinia sclerotiorum

Viruses ◽  
2020 ◽  
Vol 12 (4) ◽  
pp. 456
Author(s):  
Zhixiao Gao ◽  
Junyan Wu ◽  
Daohong Jiang ◽  
Jiatao Xie ◽  
Jiasen Cheng ◽  
...  
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Protein Biosynthesis ◽  
Secretory Proteins ◽  
Viral Mrna ◽  
Fungal Host ◽  
Reading Frame ◽  
Mutant Strains ◽  
Hypovirulent Strain ◽  
Viral Proliferation ◽  
Host Genes

We previously identified Sclerotinia sclerotiorum negative-stranded virus 1 (SsNSRV-1), the first (−) ssRNA mycovirus, associated with hypovirulence of its fungal host Sclerotinia sclerotiorum. In this study, functional analysis of Open Reading Frame Ι (ORF Ι) of SsNSRV-1 was performed. The integration and expression of ORF Ι led to defects in hyphal tips, vegetative growth, and virulence of the mutant strains of S. sclerotiorum. Further, differentially expressed genes (DEGs) responding to the expression of ORF Ι were identified by transcriptome analysis. In all, 686 DEGs consisted of 267 up-regulated genes and 419 down-regulated genes. DEGs reprogramed by ORF Ι were relevant to secretory proteins, pathogenicity, transcription, transmembrane transport, protein biosynthesis, modification, and metabolism. Alternative splicing was also detected in all mutant strains, but not in hypovirulent strain AH98, which was co-infected by SsNSRV-1 and Sclerotinia sclerotiorum hypovirus 1 (SsHV-1). Thus, the integrity of SsNSRV-1 genome may be necessary to protect viral mRNA from splicing and inactivation by the host. Taken together, the results suggested that protein ORF Ι could regulate the transcription, translation, and modification of host genes in order to facilitate viral proliferation and reduce the virulence of the host. Therefore, ORF Ι may be a potential gene used for the prevention of S. sclerotiorum.

scholarly journals Molecular Characterization of a Flagellar Export Locus of Helicobacter pylori

1999 ◽  
Vol 67 (5) ◽  
pp. 2060-2070 ◽  
Author(s):  
Steffen Porwollik ◽  
Brian Noonan ◽  
Paul W. O’Toole
Keyword(s):  
Helicobacter Pylori ◽  
Virulence Factor ◽  
Housekeeping Genes ◽  
Reading Frame ◽  
Reverse Transcription Pcr ◽  
Mutant Strains ◽  
H Pylori ◽  
Export Protein ◽  
Successful Colonization

ABSTRACT Motility of Helicobacter species has been shown to be essential for successful colonization of the host. We have investigated the organization of a flagellar export locus in Helicobacter pylori. A 7-kb fragment of the H. pylori CCUG 17874 genome was cloned and sequenced, revealing an operon comprising an open reading frame of unknown function (ORF03), essential housekeeping genes (ileS and murB), flagellar export genes (fliI and fliQ), and a homolog to a gene implicated in virulence factor transport in other pathogens (virB11). A promoter for this operon, showing similarity to the Escherichia coli ς70 consensus, was identified by primer extension. Cotranscription of the genes in the operon was demonstrated by reverse transcription-PCR, and transcription of virB11, fliI, fliQ, andmurB was detected in human or mouse biopsies obtained from infected hosts. The genetic organization of this locus was conserved in a panel of H. pylori clinical isolates. EngineeredfliI and fliQ mutant strains were completely aflagellate and nonmotile, whereas a virB11 mutant still produced flagella. The fliI and fliQ mutant strains produced reduced levels of flagellin and the hook protein FlgE. Production of OMP4, a member of the outer membrane protein family identified in H. pylori 26695, was reduced in both thevirB11 mutant and the fliI mutant, suggesting related functions of the virulence factor export protein (VirB11) and the flagellar export component (FliI).

scholarly journals Characterization of Hypovirus-Derived Small RNAs Generated in the Chestnut Blight Fungus by an Inducible DCL-2-Dependent Pathway

2008 ◽  
Vol 82 (6) ◽  
pp. 2613-2619 ◽  
Author(s):  
Xuemin Zhang ◽  
Gert C. Segers ◽  
Qihong Sun ◽  
Fuyou Deng ◽  
Donald L. Nuss
Keyword(s):  
Small Rnas ◽  
Rna Silencing ◽  
Cryphonectria Parasitica ◽  
Chestnut Blight ◽  
Fungal Host ◽  
Chestnut Blight Fungus ◽  
Mutant Strains ◽  
Suppressor Of Rna Silencing ◽  
Dependent Pathway

ABSTRACT The disruption of one of two dicer genes, dcl-2, of the chestnut blight fungus Cryphonectria parasitica was recently shown to increase susceptibility to mycovirus infection (G. C. Segers, X. Zhang, F. Deng, Q. Sun, and D. L. Nuss, Proc. Natl. Acad. Sci. USA 104:12902-12906, 2007). We now report the accumulation of virus-derived small RNAs (vsRNAs) in hypovirus CHV1-EP713-infected wild-type and dicer gene dcl-1 mutant C. parasitica strains but not in hypovirus-infected dcl-2 mutant and dcl-1 dcl-2 double-mutant strains. The CHV1-EP713 vsRNAs were produced from both the positive and negative viral RNA strands at a ratio of 3:2 in a nonrandom distribution along the viral genome. We also show that C. parasitica responds to hypovirus and mycoreovirus infections with a significant increase (12- to 20-fold) in dcl-2 expression while the expression of dcl-1 is increased only modestly (2-fold). The expression of dcl-2 is further increased (∼35-fold) following infection with a hypovirus CHV1-EP713 mutant that lacks the p29 suppressor of RNA silencing. The combined results demonstrate the biogenesis of mycovirus-derived small RNAs in a fungal host through the action of a specific dicer gene, dcl-2. They also reveal that dcl-2 expression is significantly induced in response to mycovirus infection by a mechanism that appears to be repressed by the hypovirus-encoded p29 suppressor of RNA silencing.

scholarly journals Inhibition of Biosynthesis of Human Endothelin B Receptor by the Cyclodepsipeptide Cotransin

2011 ◽  
Vol 286 (41) ◽  
pp. 35588-35600 ◽  
Author(s):  
Carolin Westendorf ◽  
Antje Schmidt ◽  
Irene Coin ◽  
Jens Furkert ◽  
Ingrid Ridelis ◽  
...  
Keyword(s):  
G Protein ◽  
Signal Sequence ◽  
Protein Biosynthesis ◽  
G Protein Coupled Receptors ◽  
Small Subset ◽  
Secretory Proteins ◽  
Endoplasmic Reticulum Membrane ◽  
Endothelin B Receptor ◽  
Endothelin B ◽  
G Protein Coupled

The specific inhibition of the biosynthesis of target proteins is a relatively novel strategy in pharmacology and is based mainly on antisense approaches (e.g. antisense oligonucleotides or RNA interference). Recently, a novel class of substances was described acting at a later step of protein biosynthesis. The cyclic heptadepsipeptides CAM741 and cotransin were shown to inhibit selectively the biosynthesis of a small subset of secretory proteins by preventing stable insertion of the nascent chains into the Sec61 translocon complex at the endoplasmic reticulum membrane (Besemer, J., Harant, H., Wang, S., Oberhauser, B., Marquardt, K., Foster, C. A., Schreiner, E. P., de Vries, J. E., Dascher-Nadel, C., and Lindley, I. J. (2005) Nature 436, 290–293; Garrison, J. L., Kunkel, E. J., Hegde, R. S., and Taunton, J. (2005) Nature 436, 285–289). These peptides act in a signal sequence-discriminatory manner, which explains their selectivity. Here, we have analyzed the cotransin sensitivity of various G protein-coupled receptors in transfected HEK 293 cells. We show that the biosynthesis of the human endothelin B receptor (ETBR) is highly sensitive to cotransin, in contrast to that of the other G protein-coupled receptors analyzed. Using a novel biosynthesis assay based on fusions with the photoconvertible Kaede protein, we show that the IC50 value of cotransin action on ETBR biosynthesis is 5.4 μm and that ETBR signaling could be completely blocked by treating cells with 30 μm cotransin. Taken together, our data add an integral membrane protein, namely the ETBR, to the small group of cotransin-sensitive proteins.

Functional ramifications of FRET-detected nascent chain folding far inside the membrane-bound ribosome

2004 ◽  
Vol 32 (5) ◽  
pp. 668-672 ◽  
Author(s):  
A.E. Johnson
Keyword(s):  
Protein Trafficking ◽  
Protein Biosynthesis ◽  
Ribosomal Subunit ◽  
Regulatory Control ◽  
Secretory Proteins ◽  
Induced Folding ◽  
Ribosomal Tunnel ◽  
Nascent Chain ◽  
Membrane Bound ◽  
Transmembrane Sequence

During protein biosynthesis, nascent protein chains are directed along a long narrow tunnel that spans the large ribosomal subunit. It has recently become clear that this structural feature has evolved to effect regulatory control over aspects of protein synthesis and protein trafficking. Since this control is nascent chain-specific, ribosomal components that form the tunnel must be involved in recognizing selected nascent proteins as they pass by. The present study focuses on one such situation in which nascent secretory proteins and membrane proteins are distinguished by the ribosome-induced folding of the latter's hydrophobic transmembrane sequence far inside the ribosomal tunnel and close to the peptidyltransferase centre.

scholarly journals Molecular characterization of two positive-strand RNA viruses co-infecting a hypovirulent strain of Sclerotinia sclerotiorum

Virology ◽  
2014 ◽  
Vol 464-465 ◽  
pp. 450-459 ◽  
Author(s):  
Zijin Hu ◽  
Songsong Wu ◽  
Jiasen Cheng ◽  
Yanping Fu ◽  
Daohong Jiang ◽  
...  
Keyword(s):  
Molecular Characterization ◽  
Sclerotinia Sclerotiorum ◽  
Rna Viruses ◽  
Positive Strand ◽  
Hypovirulent Strain ◽  
Positive Strand Rna

scholarly journals Mechanisms of Resistance to Chloramphenicol in Pseudomonas putida KT2440

2011 ◽  
Vol 56 (2) ◽  
pp. 1001-1009 ◽  
Author(s):  
Matilde Fernández ◽  
Susana Conde ◽  
Jesús de la Torre ◽  
Carlos Molina-Santiago ◽  
Juan-Luis Ramos ◽  
...  
Keyword(s):  
Pseudomonas Putida ◽  
Efflux Pump ◽  
Protein Biosynthesis ◽  
Cellular Stress Response ◽  
Knockout Mutant ◽  
Pseudomonas Putida Kt2440 ◽  
Altered Expression ◽  
Content Type ◽  
Reading Frame ◽  
A Genome

ABSTRACTPseudomonas putidaKT2440 is a chloramphenicol-resistant bacterium that is able to grow in the presence of this antibiotic at a concentration of up to 25 μg/ml. Transcriptomic analyses revealed that the expression profile of 102 genes changed in response to this concentration of chloramphenicol in the culture medium. The genes that showed altered expression include those involved in general metabolism, cellular stress response, gene regulation, efflux pump transporters, and protein biosynthesis. Analysis of a genome-wide collection of mutants showed that survival of a knockout mutant in the TtgABC resistance-nodulation-division (RND) efflux pump and mutants in the biosynthesis of pyrroloquinoline (PQQ) were compromised in the presence of chloramphenicol. The analysis also revealed that an ABC extrusion system (PP2669/PP2668/PP2667) and the AgmR regulator (PP2665) were needed for full resistance toward chloramphenicol. Transcriptional arrays revealed that AgmR controls the expression of thepqqgenes and the operon encoding the ABC extrusion pump from the promoter upstream of open reading frame (ORF) PP2669.

Virus-like particles in hyphae and conidia of European hypovirulent (dsRNA-containing) strains of Cryphonectria parasitica

1990 ◽  
Vol 68 (1) ◽  
pp. 90-101 ◽  
Author(s):  
Joseph R. Newhouse ◽  
William L. MacDonald ◽  
Harvey C. Hoch
Keyword(s):  
Defense Response ◽  
Lipid Membrane ◽  
Virulent Strain ◽  
Lipid Extraction ◽  
Staining Technique ◽  
Cryphonectria Parasitica ◽  
Fungal Host ◽  
Virus Like Particles ◽  
Hypovirulent Strain ◽  
Endothia Parasitica

Hyphae and germinating conidia of European hypovirulent (dsRNA-containing) Cryphonectria parasitica strain Ep-50 and virulent (dsRNA-free) strain Ep-67 (isogenic derivative from Ep-50), and hyphae only of European hypovirulent (dsRNA-containing) strains Ep-4 and Euro-7 were freeze-substituted and examined for the presence of virus-like particles (VLPs) using transmission electron microscopy. Spherical, membrane-bounded VLPs, measuring 50–90 nm in diameter, were located in hyphae and conidia of hypovirulent strain Ep-50, but not virulent strain Ep-67. Hyphae of hypovirulent strains Ep-4 and Euro-7 contained VLPs similar to those found in Ep-50. The VLPs occurred in aggregates surrounded by rough endoplasmic reticulum or more rarely, scattered throughout the cytoplasm; most possessed an electron-dense core. Results of Bernhard's regressive staining technique and lipid extraction cytochemistry suggested that the particles consisted of RNA surrounded by a lipid membrane. A unique Golgi body was associated with the formation of VLPs in hypovirulent strain Ep-50. The VLPs do not resemble typical fungal viruses and may be the end product of a defense response on the part of the fungal host designed to wall off foreign nucleic acid. Key words: Endothia parasitica, mycovirus, defense response, hypovirulence, viroid, fungal Golgi.

scholarly journals Development of Mutants of Coniothyrium Minitans with Improved Efficiency for Control of Sclerotinia Sclerotiorum

2011 ◽  
Vol 51 (2) ◽  
pp. 179-183 ◽  
Author(s):  
Itamar Melo ◽  
Alex Moretini ◽  
Ana Cassiolato ◽  
Jane Faull
Keyword(s):  
Sclerotinia Sclerotiorum ◽  
Plant Tissue ◽  
Type Strain ◽  
Mycelial Growth ◽  
Wild Type Strain ◽  
Wild Type ◽  
Coniothyrium Minitans ◽  
High Concentration ◽  
Mutant Strains ◽  
Chitinase Production

Development of Mutants ofConiothyrium Minitanswith Improved Efficiency for Control ofSclerotinia SclerotiorumConiothyrium minitans(CM) is hyperparasitic toSclerotinia sclerotiorum(SS), a pathogen of many economically important crops. In this paper, we describe the isolation of improved mutants of CM, using a UV - irradiation regime, with altered chitinase production and tolerance to high concentration of iprodione, which are effective against SS. Three out of the 59 mutants obtained inhibited the mycelial growth of CM. Infectivity of sclerotia by the new mutants was assayed by the plant-tissue-based system using carrot segments. More than 80% of sclerotia were colonized by the mutants and the wild-type CM. The mutant strains retained ability to produce significant amounts of chitinase. The mutants differed from their wild-type strain in appearance, morphology and sporulation. In conclusion, the results presented here provide evidence that the new biotypes ofC. minitansare effective in controllingS. sclerotiorum.

scholarly journals Identification of Hopanoid Biosynthesis Genes Involved in Polymyxin Resistance in Burkholderia multivorans

2011 ◽  
Vol 56 (1) ◽  
pp. 464-471 ◽  
Author(s):  
Rebecca J. Malott ◽  
Barbara R. Steen-Kinnaird ◽  
Tracy D. Lee ◽  
David P. Speert
Keyword(s):  
Burkholderia Cepacia ◽  
Polymyxin B ◽  
Biosynthesis Gene Cluster ◽  
Content Type ◽  
Reading Frame ◽  
Burkholderia Multivorans ◽  
Mutant Strains ◽  
Outer Membrane Permeability ◽  
Increased Susceptibility ◽  
Lps Binding

ABSTRACTA major challenge to clinical therapy ofBurkholderia cepaciacomplex (Bcc) pulmonary infections is their innate resistance to a broad range of antimicrobials, including polycationic agents such as aminoglycosides, polymyxins, and cationic peptides. To identify genetic loci associated with this phenotype, a transposon mutant library was constructed inB. multivoransATCC 17616 and screened for increased susceptibility to polymyxin B. Compared to the parent strain, mutant 26D7 exhibited 8- and 16-fold increases in susceptibility to polymyxin B and colistin, respectively. Genetic analysis of mutant 26D7 indicated that the transposon inserted into open reading frame (ORF) Bmul_2133, part of a putative hopanoid biosynthesis gene cluster. A strain with a mutation in another ORF in this cluster, Bmul_2134, was constructed and named RMI19. Mutant RMI19 also had increased polymyxin susceptibility. Hopanoids are analogues of eukaryotic sterols involved in membrane stability and barrier function. Strains with mutations in Bmul_2133 and Bmul_2134 showed increased permeability to 1-N-phenylnaphthylamine in the presence of increasing concentrations of polymyxin, suggesting that the putative hopanoid biosynthesis genes are involved in stabilizing outer membrane permeability, contributing to polymyxin resistance. Results from a dansyl-polymyxin binding assay demonstrated that polymyxin B does not bind well to the parent or mutant strains, suggesting that Bmul_2133 and Bmul_2134 contribute to polymyxin B resistance by a mechanism that is independent of lipopolysaccharide (LPS) binding. Through this work, we propose a role for hopanoid biosynthesis as part of the multiple antimicrobial resistance phenotype in Bcc bacteria.

scholarly journals Transport of Axl2p Depends on Erv14p, an ER–Vesicle Protein Related to the Drosophila cornichon Gene Product

1998 ◽  
Vol 142 (5) ◽  
pp. 1209-1222 ◽  
Author(s):  
Jacqueline Powers ◽  
Charles Barlowe
Keyword(s):  
Gene Product ◽  
Integral Membrane Protein ◽  
Secretory Protein ◽  
Yeast Cells ◽  
Secretory Proteins ◽  
Reading Frame ◽  
Transport Vesicles ◽  
Egg Chambers ◽  
Vesicle Protein ◽  
Bud Site

COPII-coated ER-derived transport vesicles from Saccharomyces cerevisiae contain a distinct set of membrane-bound polypeptides. One of these polypeptides, termed Erv14p (ER–vesicle protein of 14 kD), corresponds to an open reading frame on yeast chromosome VII that is predicted to encode an integral membrane protein and shares sequence identity with the Drosophila cornichon gene product. Experiments with an epitope-tagged version of Erv14p indicate that this protein localizes to the ER and is selectively packaged into COPII-coated vesicles. Haploid cells that lack Erv14p are viable but display a modest defect in bud site selection because a transmembrane secretory protein, Axl2p, is not efficiently delivered to the cell surface. Axl2p is required for selection of axial growth sites and normally localizes to nascent bud tips or the mother bud neck. In erv14Δ strains, Axl2p accumulates in the ER while other secretory proteins are transported at wild-type rates. We propose that Erv14p is required for the export of specific secretory cargo from the ER. The polarity defect of erv14Δ yeast cells is reminiscent of cornichon mutants, in which egg chambers fail to establish proper asymmetry during early stages of oogenesis. These results suggest an unforeseen conservation in mechanisms producing cell polarity shared between yeast and Drosophila.

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