Plant defenses against pathogens and insects are regulated differentially by cross-communicating signaling pathways in which salicylic acid (SA), jasmonic acid (JA) and ethylene (ET) play key roles. To understand how plants integrate pathogen- and insect-induced signals into specific defense responses, we monitored the dynamics of SA, JA, and ET signaling in Arabidopsis after attack by a set of microbial pathogens and herbivorous insects with different modes of attack. Arabidopsis plants were exposed to a pathogenic leaf bacterium (Pseudomonas syringae pv. tomato), a pathogenic leaf fungus (Alternaria brassicicola), tissue-chewing caterpillars (Pieris rapae), cell-content-feeding thrips (Frankliniella occidentalis), or phloem-feeding aphids (Myzus persicae). Monitoring the signal signature in each plant-attacker combination showed that the kinetics of SA, JA, and ET production varies greatly in both quantity and timing. Analysis of global gene expression profiles demonstrated that the signal signature characteristic of each Arabidopsis-attacker combination is orchestrated into a surprisingly complex set of transcriptional alterations in which, in all cases, stress-related genes are overrepresented. Comparison of the transcript profiles revealed that consistent changes induced by pathogens and insects with very different modes of attack can show considerable overlap. Of all consistent changes induced by A. brassicicola, P. rapae, and F. occidentalis, more than 50% were also induced consistently by P. syringae. Notably, although these four attackers all stimulated JA biosynthesis, the majority of the changes in JA-responsive gene expression were attacker-specific. All together our study shows that SA, JA, and ET play a primary role in the orchestration of the plant's defense response, but other regulatory mechanisms, such as pathway cross-talk or additional attacker-induced signals, eventually shape the highly complex attacker-specific defense response.
Signal signature and transcriptome changes of Arabidopsis during pathogen and insect attack.
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View SamplesN6-methyladenosine RNA (m6A) is the most abundant internal mRNA modification in mammals. While its role in the regulation of posttranscriptional gene expression is beginning to be unveiled, its function during development of complex organisms is poorly understood. Here, we identify Spenito as a novel member of the methyltransferase complex and show that m6A in Drosophila is necessary for proper synaptic growth, and in regulation of early steps of pre-mRNA splicing. Splicing of Sex-lethal and of its downstream targets are defective in animals lacking m6A, revealing also important roles in sex determination and dosage compensation. Finally, we implicate the nuclear m6A reader protein, YT521-B, as a crucial effector of m6A modifications in vivo. Altogether, our work provides important novel insights into m6A biology through identification and characterization of both m6A-writing and -reading proteins in Drosophila and their effects on splicing, neurogenesis and sex-determination within the context of the whole animal. Overall design: RNA seq in Drosophila melanogaster (flies) (3 Conditions, triplicates)
m<sup>6</sup>A modulates neuronal functions and sex determination in Drosophila.
Sex, Specimen part, Subject
View SamplesNaturally occurring CD25+CD4+ regulatory T cells (T reg cells) are currently intensively characterized because of their major importance in modulating host responses to tumors and infections, in preventing transplant rejection, and in inhibiting the development of autoimmunity and allergy. Originally, CD4+ T reg cells were identified exclusively by the constitutive expression of CD25, and many in vivo experiments have been performed using depleting antibodies directed against CD25. However, both the existence of CD25 T reg cells, especially within peripheral tissues, as well as the expression of CD25 on activated conventional T cells, which precludes discrimination between T reg cells and activated conventional T cells, limits the interpretation of data obtained by the use of anti-CD25 depleting antibodies. The most specific T reg cell marker currently known is the forkhead box transcription factor Foxp3, which has been shown to be expressed specifically in mouse CD4+ T reg cells and acts as a master switch in the regulation of their development and function. To address the question of the in vivo role of T reg cells in immunopathology, we have generated bacterial artificial chromosome (BAC)transgenic mice termed depletion of regulatory T cell (DEREG) mice, which express a diphtheria toxin receptor (DTR) enhanced GFP (eGFP) fusion protein under the control of the foxp3 locus, allowing both detection and inducible depletion of Foxp3+ T reg cells. The gene expression profile of both CD4+eGFP+FoxP3+ and CD4+eGFPnegFoxP3neg cells isolated from DEREG mice was here analyzed by micro array.
Immunostimulatory RNA blocks suppression by regulatory T cells.
Specimen part
View SamplesDuring development, thymocytes bearing a moderately self-reactive T cell receptor (TCR) can be selected to become regulatory T (Treg) cells. Several observations suggest that also in the periphery mature Treg cells continuously receive self-reactive TCR signals. However, the importance of this inherent autoreactivity for Treg cell biology remains poorly defined.
Continuous T cell receptor signals maintain a functional regulatory T cell pool.
Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Antiviral Protection via RdRP-Mediated Stable Activation of Innate Immunity.
Sex, Specimen part
View SamplesPreviously, we reported that mice made transgenic for a picornaviral RdRP the 3Dpol protein of Theilers murine encephalomyelitis virus (TMEV) suppress infection by diverse viral families. How the picornaviral RdRP transgene exerted antiviral protection in vivo was not known. To investigate the molecular mechanism, we determined gene expression profiles in spinal cords of WT and RdRP transgenic mice prior to (baseline) and after (2 days) infection with Encephalomyocarditis Virus (EMCV).
Antiviral Protection via RdRP-Mediated Stable Activation of Innate Immunity.
Sex
View SamplesPreviously, we reported that mice made transgenic for a picornaviral RdRP the 3Dpol protein of Theilers murine encephalomyelitis virus (TMEV) suppress infection by diverse viruses. Using mouse genetic studies, we determined that uninfected RdRP transgenic mice inherently induce an arsenel of prominent antiviral effectors and that this phenotype is MDA5-, MAVS- and IFNR-dependent. To determine the mechanism underlying MDA5 activation and induction of constitutive antiviral signaling by the picornaviral RdRP, we constructed mutant RdRP transgenes. First, we introduced pervasive, coding-neutral point mutations into the RdRP cDNA to maximally disrupt primary and secondary RNA structure (RdRPrna). Another mutant, RdRPcat, lacks catalytic activity due to alanine substitution of the key catalytic center triad aspartate residues (D233, D328, and D329), but is otherwise intact at the nucleotide and amino acid levels. The WT, RdRPrna, and RdRPcat versions of the RdRP transgenes were transduced with lentiviral vectors into human THP-1 monocytes, with RdRP mRNA transcription controlled by the Spleen Focus Forming Virus (SFFV) promoter. In parallel a control cell line transduced with a vector lacking any RdRP transgene (null THP-1) was generated.
Antiviral Protection via RdRP-Mediated Stable Activation of Innate Immunity.
Specimen part
View SamplesPreviously, we reported that mice made transgenic for a picornaviral RdRP the 3Dpol protein of Theilers murine encephalomyelitis virus (TMEV) suppress infection by diverse viruses. Using mouse genetic studies, we determined that uninfected RdRP transgenic mice inherently induce an arsenel of prominent antiviral effectors and that this phenotype is MDA5-, MAVS- and IFNR-dependent. To determine the mechanism underlying MDA5 activation and induction of constitutive antiviral signaling by the picornaviral RdRP, we constructed mutant RdRP transgenes. First, we introduced pervasive, coding-neutral point mutations into the RdRP cDNA to maximally disrupt primary and secondary RNA structure (RdRPrna). Another mutant, RdRPcat, lacks catalytic activity due to alanine substitution of the key catalytic center triad aspartate residues (D233, D328, and D329), but is otherwise intact at the nucleotide and amino acid levels. The WT, RdRPrna, and RdRPcat versions of the RdRP transgenes were transduced with lentiviral vectors into human THP-1 monocytes, with RdRP mRNA transcription controlled by the Spleen Focus Forming Virus (SFFV) promoter. In parallel a control cell line transduced with a vector lacking any RdRP transgene (null THP-1) was generated.
Antiviral Protection via RdRP-Mediated Stable Activation of Innate Immunity.
Specimen part
View SamplesPreviously, we reported that mice made transgenic for a picornaviral RdRP the 3Dpol protein of Theilers murine encephalomyelitis virus (TMEV) suppress infection by diverse viruses. Using mouse genetic studies, we determined that uninfected RdRP transgenic mice inherently induce an arsenel of prominent antiviral effectors and that this phenotype is MDA5-, MAVS- and IFNR-dependent. To determine the mechanism underlying MDA5 activation and induction of constitutive antiviral signaling by the picornaviral RdRP, we constructed mutant RdRP transgenes. First, we introduced pervasive, coding-neutral point mutations into the RdRP cDNA to maximally disrupt primary and secondary RNA structure (RdRPrna). Another mutant, RdRPcat, lacks catalytic activity due to alanine substitution of the key catalytic center triad aspartate residues (D233, D328, and D329), but is otherwise intact at the nucleotide and amino acid levels. The WT, RdRPrna, and RdRPcat versions of the RdRP transgenes were transduced with lentiviral vectors into human THP-1 monocytes, with RdRP mRNA transcription controlled by the Spleen Focus Forming Virus (SFFV) promoter. In parallel a control cell line transduced with a vector lacking any RdRP transgene (null THP-1) was generated.
Antiviral Protection via RdRP-Mediated Stable Activation of Innate Immunity.
Specimen part
View SamplesPreviously, we reported that mice made transgenic for a picornaviral RdRP the 3Dpol protein of Theilers murine encephalomyelitis virus (TMEV) suppress infection by diverse viral families. How the picornaviral RdRP transgene exerted antiviral protection in vivo was not known. To investigate the molecular mechanism, we determined gene expression profiles in spinal cords of WT and RdRP transgenic mice prior to (baseline) and after (2 days) infection with Encephalomyocarditis Virus (EMCV).
Antiviral Protection via RdRP-Mediated Stable Activation of Innate Immunity.
Sex
View Samples