Host signals in fungal gene expression involved in penetration into the host

1995 ◽  
Vol 73 (S1) ◽  
pp. 1160-1168 ◽  
Author(s):  
Pappachan E. Kolattukudy ◽  
Daoxin Li ◽  
Cheng-Shine Hwang ◽  
Moshe A. Flaishman
Keyword(s):  
Gene Expression ◽  
Fungal Spores ◽  
Persea Americana ◽  
Appressorium Formation ◽  
Small Proteins ◽  
Surface Wax ◽  
Plant Signals ◽  
Host Signals ◽  
Fungal Gene Expression ◽  
Host Signal

Fungal spores, on contact with their hosts, perceive the plant signals and consequently initiate gene expression that enables the fungus to penetrate through the host barriers. Germination and appressorium formation by Colletotrichum gloeosporioides spore is induced by host surface wax on the growing avocado (Persea americana) fruits and, at ripening of the fruit, ethylene induces multiple appressorium formation. Both the wax and ethylene may use phosphorylation of 29- and 43-kDa proteins in the signal transduction. Unique genes that are expressed during appressorium formation induced by the host signal were cloned and sequenced. These include cap3 and cap5 that encode cysteine-rich small proteins, cap22 that encodes a secreted glycoprotein found in the appressorial wall, and cap20 whose disruption drastically decreases virulence. Disruption of cutinase gene drastically reduces the virulence of Fusarium solani pisi on pea (Pisum sativum L.). The promoter elements in cutinase gene involved in the induction of this gene by the hydroxy fatty acid monomers of cutin were identified and transcription factors that bind these elements were cloned. One of them, that binds to a palindrome, essential for cutinase induction, was found to be phosphorylated. Several proteins kinases from F. solani pisi were cloned. Key words: appressorium, cutin, cutinase, ethylene, gene disruption, protein phosphorylation, protein kinase, transcription factor.

scholarly journals TheC. difficile clnRABoperon initiates adaptations to the host environment in response to LL-37

2018 ◽  
Author(s):  
Emily C. Woods ◽  
Adrianne N. Edwards ◽  
Shonna M. McBride
Keyword(s):  
Gene Expression ◽  
Diarrheal Disease ◽  
Regulatory System ◽  
Innate Immune ◽  
Cellular Transport ◽  
Intestinal Environment ◽  
Host Defense Peptide ◽  
Surface Active ◽  
Pleiotropic Regulator ◽  
Host Signal

ABSTRACTTo cause disease,Clostridioides(Clostridium)difficilemust resist killing by innate immune effectors in the intestine, including the host antimicrobial peptide, cathelicidin (LL-37). The mechanisms that enableC. difficileto adapt to the intestine in the presence of antimicrobial peptides are unknown. Expression analyses revealed an operon,CD630_16170-CD630_16190(clnRAB), which is highly induced by LL-37 and is not expressed in response to other cell-surface active antimicrobials. This operon encodes a predicted transcriptional regulator (clnR) and an ABC transporter system (clnAB), all of which are required for function. Analyses of aclnRmutant indicate that ClnR is a pleiotropic regulator that directly binds to LL-37 and controls expression of numerous genes, including many involved in metabolism, cellular transport, signaling, gene regulation, and pathogenesis. The data suggest that ClnRAB is a novel regulatory mechanism that senses LL-37 as a host signal and regulates gene expression to adapt to the host intestinal environment during infection.Author SummaryC. difficileis a major nosocomial pathogen that causes severe diarrheal disease. ThoughC. difficileis known to inhabit the human gastrointestinal tract, the mechanisms that allow this pathogen to adapt to the intestine and survive host defenses are not known. In this work, we investigated the response ofC. difficileto the host defense peptide, LL-37, to determine the mechanisms underlying host adaptation and survival. Expression analyses revealed a previously unknown locus, which we namedclnRAB, that is highly induced by LL-37 and acts as a global regulator of gene expression inC. difficile. Mutant analyses indicate that ClnRAB is a novel regulatory system that senses LL-37 as a host signal to regulate adaptation to the intestinal environment.

scholarly journals Contrasting Effects of σE on Compartmentalization of σF Activity during Sporulation of Bacillus subtilis

2004 ◽  
Vol 186 (7) ◽  
pp. 1983-1990 ◽  
Author(s):  
David W. Hilbert ◽  
Vasant K. Chary ◽  
Patrick J. Piggot
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Bacillus Subtilis ◽  
Mother Cell ◽  
Cell Fates ◽  
Gene Encoding ◽  
Primitive Form ◽  
Small Proteins ◽  
Dna Translocase

ABSTRACT Spore formation by Bacillus subtilis is a primitive form of development. In response to nutrient starvation and high cell density, B. subtilis divides asymmetrically, resulting in two cells with different sizes and cell fates. Immediately after division, the transcription factor σF becomes active in the smaller prespore, which is followed by the activation of σE in the larger mother cell. In this report, we examine the role of the mother cell-specific transcription factor σE in maintaining the compartmentalization of gene expression during development. We have studied a strain with a deletion of the spoIIIE gene, encoding a DNA translocase, that exhibits uncompartmentalized σF activity. We have determined that the deletion of spoIIIE alone does not substantially impact compartmentalization, but in the spoIIIE mutant, the expression of putative peptidoglycan hydrolases under the control of σE in the mother cell destroys the integrity of the septum. As a consequence, small proteins can cross the septum, thereby abolishing compartmentalization. In addition, we have found that in a mutant with partially impaired control of σF, the activation of σE in the mother cell is important to prevent the activation of σF in this compartment. Therefore, the activity of σE can either maintain or abolish the compartmentalization of σF, depending upon the genetic makeup of the strain. We conclude that σE activity must be carefully regulated in order to maintain compartmentalization of gene expression during development.

scholarly journals Novel Genes of Fusarium graminearum That Negatively Regulate Deoxynivalenol Production and Virulence

2009 ◽  
Vol 22 (12) ◽  
pp. 1588-1600 ◽  
Author(s):  
Donald M. Gardiner ◽  
Kemal Kazan ◽  
John M. Manners
Keyword(s):  
Gene Expression ◽  
Fusarium Graminearum ◽  
Global Analysis ◽  
Gene Clusters ◽  
Head Blight ◽  
Knock Out ◽  
Serious Disease ◽  
Amine Compounds ◽  
Fungal Genes ◽  
Fungal Gene Expression

Fusarium head blight of wheat, caused by Fusarium graminearum, is a serious disease resulting in both reduced yields and contamination of grain with trichothecene toxins, with severe consequences for mammalian health. Recently, we have identified several related amine compounds such as agmatine and putrescine that promote the production of high levels of trichothecene toxins, such as deoxynivalenol (DON), in culture by F. graminearum and F. sporotrichioides. Here, a global analysis of fungal gene expression using the Affymetrix Fusarium GeneChip during culture under DON-inducing conditions compared with noninducing conditions is reported. Agmatine differentially regulated a large number of fungal genes, including both known and previously uncharacterized putative secondary metabolite biosynthetic gene clusters. In silico prediction of binding sites for the transcriptional regulator (TRI6) controlling TRI gene expression and gene expression analysis in a TRI6 mutant of F. graminearum showed that three of the differentially regulated genes were under the control of TRI6. Gene knock-out mutations of two of these genes resulted in mutants with massively increased production of DON and increased aggressiveness toward wheat. Our results not only identify a novel mechanism of negative regulation of DON production and virulence in F. graminearum but also point out the potential of this pathogen to evolve with an ability to produce massively increased amounts of toxins and increased virulence.

scholarly journals Differential accumulation of poly(A)+ RNA between virulent and double-stranded RNA-induced hypovirulent strains of Cryphonectria (Endothia) parasitica.

1987 ◽  
Vol 7 (10) ◽  
pp. 3688-3693 ◽  
Author(s):  
W A Powell ◽  
N K Van Alfen
Keyword(s):  
Gene Expression ◽  
Specific Effect ◽  
Rna Sequences ◽  
Double Stranded Rna ◽  
Total Rna ◽  
Rna Sequence ◽  
Differential Hybridization ◽  
Endothia Parasitica ◽  
Fungal Gene Expression ◽  
Fungal Gene

The double-stranded RNA responsible for transmissible hypovirulence in Cryphonectria (Endothia) parasitica was found to affect the accumulation of specific poly(A)+ RNA. Using differential hybridization techniques, two genes were isolated, Vir1 and Vir2, which were specifically expressed as poly(A)+ RNAs in the virulent cells. The highly expressed RNA sequences from these genes were not found in total RNA isolated from either American or European hypovirulent strains, although the genes were present in their genomes. Other virulence- and hypovirulence-specific RNA sequences were also detected. One isolated hypovirulence-specific RNA sequence was expressed in both virulent and hypovirulent cells, but in a two- to fourfold-higher concentration in the hypovirulent cells. The results show that hypovirulence is associated with concurrent changes in a few highly expressed poly(A)+ RNAs, which suggests a specific effect of the double-stranded RNA on fungal gene expression.

scholarly journals pH Regulation of Ammonia Secretion by Colletotrichum gloeosporioides and Its Effect on Appressorium Formation and Pathogenicity

2010 ◽  
Vol 23 (3) ◽  
pp. 304-316 ◽  
Author(s):  
Itay Miyara ◽  
Hadas Shafran ◽  
Maayan Davidzon ◽  
Amir Sherman ◽  
Dov Prusky
Keyword(s):  
Ph Regulation ◽  
Persea Americana ◽  
Appressorium Formation ◽  
Ammonia Metabolism ◽  
Ammonia Accumulation ◽  
Avocado Fruit ◽  
In The Wild ◽  
Ammonia Addition ◽  
Colletotrichum Spp ◽  
Appressoria Formation

Host-tissue alkalinization via ammonia accumulation is key to Colletotrichum spp. colonization. Using macroarrays carrying C. gloeosporioides cDNAs, we monitored gene expression during the alkalinization process. A set of genes involved in synthesis and catabolism of ammonia accumulation were identified. Expression of NAD+-specific glutamate dehydrogenase (GDH2, encoding ammonia synthesis) and the ammonia exporter AMET were induced at pH 4.0 to 4.5. Conversely, ammonia uptake and transcript activation of the ammonia and glutamate importers (MEP and GLT, respectively) and glutamine synthase (GS1) were higher at pH 6.0 to 7.0. Accumulated ammonia in the wild-type mycelium decreased during ambient alkalinization, concurrent with increased GS1 expression. Δpac1 mutants of C. gloeosporioides, which are sensitive to alkaline pH changes, showed upregulation of the acid-expressed GDH2 and downregulation of the alkaline-expressed GS1, resulting in 60% higher ammonia accumulation inside the mycelium. Δgdh2 strains of C. gloeosporioides, impaired in ammonia production, showed 85% inhibition in appressorium formation followed by reduced colonization on avocado fruit (Persea americana cv. Fuerte) pericarp, while exogenic ammonia addition restored appressoria formation. Thus the modulation of genes involved in ammonia metabolism and catabolism by C. gloeosporioides is ambient pH–dependent. Aside from its contribution to necrotrophic stages, ammonia accumulation by germinating spores regulates appressorium formation and determines the initiation of biotrophic stages of avocado-fruit colonization by Colletotrichum spp.

scholarly journals Polycysteine-encoding leaderless short ORFs function as cysteine-responsive attenuators of operonic gene expression in mycobacteria

2019 ◽  
Author(s):  
Jill G. Canestrari ◽  
Erica Lasek-Nesselquist ◽  
Ashutosh Upadhyay ◽  
Martina Rofaeil ◽  
Matthew M. Champion ◽  
...  
Keyword(s):  
Gene Expression ◽  
Mutational Analysis ◽  
Open Reading Frames ◽  
Level Control ◽  
Small Proteins ◽  
Short Orfs ◽  
The Many ◽  
Ribosome Pausing ◽  
Proteomic Responses ◽  
Open Question

ABSTRACTGenome-wide transcriptomic analyses have revealed abundant expressed short open reading frames (ORFs) in bacteria. Whether these short ORFs, or the small proteins they encode, are functional remains an open question. One quarter of mycobacterial mRNAs are leaderless, beginning with a 5’-AUG or GUG initiation codon. Leaderless mRNAs often encode unannotated short ORFs as the first gene of a polycistronic transcript. Here we show that polycysteine-encoding leaderless short ORFs function as cysteine-responsive attenuators of operonic gene expression. Detailed mutational analysis shows that one polycysteine short ORF controls expression of the downstream genes. Our data indicate that ribosomes stalled in the polycysteine tract block mRNA structures that otherwise sequester the ribosome-binding site of the 3’gene. We assessed endogenous proteomic responses to cysteine limitation in Mycobacterium smegmatis using mass spectrometry. Six cysteine metabolic loci having unannotated polycysteine-encoding leaderless short ORF architectures responded to cysteine limitation, revealing widespread cysteine-responsive attenuation in mycobacteria. Individual leaderless short ORFs confer independent operon-level control, while their shared dependence on cysteine ensures a collective response mediated by ribosome pausing. We propose the term ribulon to classify ribosome-directed regulons. Regulon-level coordination by ribosomes on sensory short ORFs illustrates one utility of the many unannotated short ORFs expressed in bacterial genomes.

scholarly journals Biological Effect of Organically Coated Grias neuberthii and Persea americana Silver Nanoparticles on HeLa and MCF-7 Cancer Cell Lines

2018 ◽  
Vol 2018 ◽  
pp. 1-11 ◽  
Author(s):  
Lizeth Salazar ◽  
María José Vallejo López ◽  
Marcelo Grijalva ◽  
Luis Castillo ◽  
Alexander Maldonado
Keyword(s):  
Gene Expression ◽  
Transcription Factor ◽  
Cell Viability ◽  
Cell Lines ◽  
Cancer Cell ◽  
Hela Cells ◽  
Biological Effect ◽  
Persea Americana ◽  
Expression Levels ◽  
Mcf 7

The aim of this study was to assess the biological effect of organically coated Grias neuberthii (piton) fruit and Persea americana (avocado) leaves nanoparticles (NPs) on cervical cancer (HeLa) and breast adenocarcinoma (MCF-7) cells with an emphasis on gene expression (p53 transcription factor and glutathione-S-transferase GST) and cell viability. UV-Vis spectroscopy analysis showed that synthesized AgNPs remained partially stable under cell culture conditions. HeLa cells remained viable when exposed to piton and avocado AgNPs. A statistically significant, dose-dependent cytotoxic response to both AgNPs was found on the breast cancer (MCF-7) cell line at concentrations above 50 µM. While expression levels of transcription factor p53 showed downregulation in treated MCF-7 and HeLa cells, GST expression was not affected in both cell lines treated. Cell viability assays along with gene expression levels in treated MCF-7 cells support a cancer cell population undergoing cell cycle arrest. The selective toxicity of biosynthesized piton/avocado AgNPs on MCF-7 cells might be of value for novel therapeutics.

FungiExp: A Comprehensive Platform For Exploring Fungal Gene Expression and Alternative Splicing Based On 35,821 RNA-Seq Experiments From 220 Fungi

2021 ◽  
Author(s):  
Jinding Liu ◽  
Fei Yin ◽  
Kun Lang ◽  
Wencai Jie ◽  
Suxu Tan ◽  
...  
Keyword(s):  
Gene Expression ◽  
Alternative Splicing ◽  
Sequence Similarity ◽  
Expression Regulation ◽  
Rna Seq ◽  
Specific Expression ◽  
Data Accessibility ◽  
Wide Range ◽  
Fungal Gene Expression ◽  
Fungal Gene

Abstract Background: RNA-seq has become a standard tool in biology and has produced large and diverse transcriptomic datasets for users to explore fungal expression regulation. Fungal alternative splicing, which is attracting increasing attention because of evolutionary adaptations to changing external conditions has not been thoroughly investigated in previous studies, unlike that of animals and plants. However, the analyses of RNA-seq datasets are made difficult by the heterogeneity of study design and complex bioinformatics approaches. Comprehensive analyses of these published datasets should contribute new insights into fungal expression regulation.Results: We have developed a web-based platform called FungiExp hosting fungal gene expression levels and alternative splicing profiles in 35,821 curated RNA-seq experiments from 220 species. It allows users to perform retrieval via diverse terms and sequence similarity. Moreover, users can customize experimental groups to perform differential and specific expression analyses. The wide range of data visualization is an additional important feature that should help users intuitively understand retrieval and analysis results.Conclusions: With its uniform data processing, easy data accessibility, convenient retrieval, and analysis functions, FungiExp is a valuable resource and tool that allows users to (re)use published RNA-seq datasets. It is accessible at http://bioinfo.njau.edu.cn/fungiExp.

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