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GSE15680
Arabidopsis thaliana
16 Downloadable Samples
Affymetrix Arabidopsis ATH1 Genome Array (ath1121501)
Description
To elucidate host processes and components required for the sustained growth and reproduction of the obligate biotrophic fungus Golovinomyces orontii on Arabidopsis thaliana, laser microdissection was used to isolate cells at the site of infection at 5 days postinfection for downstream global Arabidopsis expression profiling. Site-specific profiling increased sensitivity dramatically, allowing us to identify specific host processes, process components, and their putative regulators hidden in previous whole-leaf global expression analyses. For example, 67 transcription factors exhibited altered expression at the powdery mildew (PM) infection site, with subsets of these playing known or inferred roles in photosynthesis, cold/dehydration responses, defense, auxin signaling, and the cell cycle. Using integrated informatics analyses, we constructed putative regulatory networks for a subset of these processes and provided strong support for host cell cycle modulation at the PM infection site. Further experimentation revealed induced host endoreduplication occurred exclusively at the infection site and led us to identify MYB3R4 as a transcriptional regulator of this process. Induced endoreduplication was abrogated in myb3r4 mutants, and G. orontii growth and reproduction were reduced. This suggests that, by increasing gene copy number, localized endoreduplication serves as a mechanism to meet the enhanced metabolic demands imposed by the fungus, which acquires all its nutrients from the plant host.
Publication Title
Laser microdissection of Arabidopsis cells at the powdery mildew infection site reveals site-specific processes and regulators.
Sample Metadata Fields
Age, Specimen part
View Samples- Arabidopsis thaliana
- 8 Downloadable Samples
- Affymetrix Arabidopsis ATH1 Genome Array (ath1121501)
Description
In plants, the activation of immunity is often inversely correlated with growth. Mechanisms that plant growth in the context of pathogen challenge and immunity are unclear. Investigating Arabidopsis infection with the powdery mildew fungus, we find that the Arabidopsis atypical E2F DEL1, a transcriptional repressor known to promote cell proliferation, represses accumulation of the hormone salicylic acid (SA), an established regulator of plant immunity. DEL1 deficient plants are more resistant to pathogens and slightly smaller than wild type. The resistance and size phenotypes of DEL1 deficient plants are due to the induction of SA and activation of immunity in the absence of pathogen challenge. Moreover, Enhanced Disease Susceptibility 5 (EDS5), a SA transporter required for elevated SA and immunity, is a direct repressed target of DEL1. Together, these findings indicate that DEL1 control of SA levels contributes to regulating the balance between growth and immunity in developing leaves.
Publication Title
Atypical E2F transcriptional repressor DEL1 acts at the intersection of plant growth and immunity by controlling the hormone salicylic acid.
Sample Metadata Fields
Age, Specimen part
View Samples- Arabidopsis thaliana
- 56 Downloadable Samples
- Affymetrix Arabidopsis ATH1 Genome Array (ath1121501)
Description
Salicylic acid (SA) is a critical molecule mediating plant innate immunity with an important role limiting the growth and reproduction of the virulent powdery mildew (PM) Golovinomyces orontii on Arabidopsis thaliana. To investigate this later phase of the PM interaction, and the role played by SA, we performed replicated global expression profiling for wild type and SA biosynthetic mutant ics1 Arabidopsis from 0 to 7 days post infection. We found that ICS1-impacted genes comprise 3.8% of profiled genes with known molecular markers of Arabidopsis defense ranked very highly by the multivariate empirical Bayes statistic (T2 statistic ((Tai and Speed, 2006)). Functional analyses of T2-selected genes identified statistically significant PM-impacted processes including photosynthesis, cell wall modification, and alkaloid metabolism that are ICS1-independent. ICS1-impacted processes include redox, vacuolar transport/secretion, and signaling. Our data also supports a role for ICS1 (SA) in iron and calcium homeostasis and identifies components of SA crosstalk with other phytohormones. Through our analysis, 39 novel PMimpacted transcriptional regulators were identified. Insertion mutants in one of these regulators, PUX2, results in significantly reduced reproduction of the powdery mildew in a cell death independent manner. Though little is known about PUX2, PUX1 acts as a negative regulator of Arabidopsis CDC48 (Rancour et al., 2004; Park et al., 2007), an essential AAA-ATPase chaperone that mediates diverse cellular activities including homotypic fusion of ER and Golgi membranes, ER-associated protein degradation, cell cycle progression, and apoptosis. Future work will elucidate the functional role of the novel regulator PUX2 in PM resistance.
Publication Title
Temporal global expression data reveal known and novel salicylate-impacted processes and regulators mediating powdery mildew growth and reproduction on Arabidopsis.
Sample Metadata Fields
Age, Specimen part
View Samples- Arabidopsis thaliana
- 8 Downloadable Samples
- Affymetrix Arabidopsis ATH1 Genome Array (ath1121501)
Description
Neonicotinoid insecticides control crop pests based on their action as agonists at the insect nicotinic acetylcholine receptor which accepts chloropyridinyl- and chlorothiazolyl- analogs almost equally well. In some cases, these compounds have also been reported to enhance plant vigor and (a)biotic stress tolerance, independent of their insecticidal function. However, this mode of action has not been specifically defined. Using Arabidopsis thaliana, we show that the neonicotinoid compounds, imidacloprid (IMI) and clothianidin (CLO), via their 6-chloropyridinyl-3-carboxylic acid and 2-chlorothiazolyl-5-carboxylic acid metabolites, respectively, induce salicylic acid (SA) associated plant responses. SA is a phytohormone best known for its role in plant defense against pathogens and as an inducer of systemic acquired resistance; however, it can also modulate abiotic stress responses. These neonicotinoids effect a similar global transcriptional response to that of SA including genes involved in (a)biotic stress response. Furthermore, similar to SA, IMI and CLO induce systemic acquired resistance resulting in reduced growth of a powdery mildew pathogen. The action of CLO induces the endogenous synthesis of SA via the SA biosynthetic enzyme ICS1, with ICS1 required for CLO-induced accumulation of SA, expression of the SA marker PR1, and fully enhanced resistance to powdery mildew. In contrast, the action of IMI does not induce endogenous synthesis of SA. Instead, IMI is further bioactivated to 6-chloro-2-hydroxypyridinyl-3-carboxylic acid, which is shown here to be a potent inducer of PR1 and inhibitor of SA-sensitive enzymes. Thus, via different mechanisms, these chloropyridinyl- and chlorothiazolyl- neonicotinoids induce SA responses associated with enhanced stress tolerance.
Publication Title
Neonicotinoid insecticides induce salicylate-associated plant defense responses.
Sample Metadata Fields
Age, Specimen part
View Samples- Homo sapiens
- 2 Downloadable Samples
- Affymetrix Human Gene 1.0 ST Array (hugene10st)
Description
Induction of the transcription factor Sox2 from a doxycycline-inducible promoter in iSox2-DAOY medulloblastoma cells.
Publication Title
Elevating SOX2 levels deleteriously affects the growth of medulloblastoma and glioblastoma cells.
Sample Metadata Fields
Specimen part
View Samples- Rattus norvegicus
- 12 Downloadable Samples
- Affymetrix Rat Expression 230A Array (rae230a)
Description
Effects of hyperglycaemia and genetic background differences on renal gene expression
Publication Title
Comparative analysis of methods for gene transcription profiling data derived from different microarray technologies in rat and mouse models of diabetes.
Sample Metadata Fields
Sex, Age, Specimen part, Disease, Subject
View Samples- Homo sapiens
- 27 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
16 replication error proficient (RER-/MSI-) and 14 replication error deficient (RER+/MSI+) colorectal cancer cell lines
Publication Title
Replication error deficient and proficient colorectal cancer gene expression differences caused by 3'UTR polyT sequence deletions.
Sample Metadata Fields
Cell line
View Samples- Homo sapiens
- 66 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
Chlamydia trachomatis serovariants are responsible for either Trachoma, the leading cause of infectious blindness or sexually transmitted disease, wherein the endocervix is the most frequently infected site in women. Disease caused by Chlamydia typically involves chronic inflammation and scarring. Recent work with a live-attenuated A2497 plasmid deficient vaccine strain (A2497-) demonstrated protection in nonhuman primates against trachoma and a lack of measurable ocular pathology in A2497- infected monkeys. We therefore performed host cell transcriptome analysis of Hela cells infected with A2497 plasmid-containing (A2497) and A2497- Chlamydia over time. Our results indicate that relative to wild type A2497, the A2497- variant illicits a transcriptome response indicative of lowered inflammation response a delayed apoptosis response, a reduction in immune cell recruitement cytokine expression and a reduction in genes involved in cell proliferation and or fibrosis-like activities. The data provided here suggests a model that may explain how plasmid deficient chlamydia may provide an immuno-protective response without the pathology normally seen with plasmid-containing bacteria.
Publication Title
Transcriptional profiling of human epithelial cells infected with plasmid-bearing and plasmid-deficient Chlamydia trachomatis.
Sample Metadata Fields
Disease, Cell line
View Samples- Homo sapiens
- 8 Downloadable Samples
- Affymetrix Human Genome U133 Plus 2.0 Array (hgu133plus2)
Description
Pericryptal myofibroblasts in the colon and rectum play an important role in regulating the normal colorectal stem cell niche and facilitating tumour progression. Myofibroblasts have previously mostly been distinguished from normal fibroblasts only by the expression of smooth muscle actin (SMA). We now identify AOC3, a surface monoamine oxidase, as a new marker of myofibroblasts by showing that it is the target protein of the myofibroblast reacting monoclonal antibody (mAb), PR2D3. The normal and tumour tissue distribution and the cell line reactivity of AOC3 match that expected for myofibroblasts. We have shown that the surface expression of AOC3 is sensitive to digestion by trypsin and collagenase and that anti-AOC3 antibodies can be used for FACS sorting of myofibroblasts obtained by non-enzymatic procedures. Whole genome microarray mRNA expression profiles of myofibroblasts and skin fibroblasts revealed four additional genes that are significantly expressed differentially between these two cell types; NKX2-3 and LRRC17 are expressed in myofibroblasts and SHOX2 and TBX5 in skin fibroblasts. Transforming Growth Factor (TGF) substantially down-regulated AOC3 expression in myofibroblasts but not in skin fibroblasts, in which it dramatically increased the expression of SMA. A knockdown of NKX2-3 in myofibroblasts caused a decrease of myofibroblast-related gene expression and an increased expression of the fibroblast associated gene, SHOX2, suggesting that NKX2-3 is a key mediator for maintaining myofibroblast characteristics. Our results show that colorectal myofibroblasts, as defined by the expression of AOC3, NKX2-3 and other markers, are a distinctly different cell type from TGF activated fibroblasts.
Publication Title
Myofibroblasts are distinguished from activated skin fibroblasts by the expression of AOC3 and other associated markers.
Sample Metadata Fields
Specimen part
View Samples- Mus musculus
- 12 Downloadable Samples
- Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
In the past decade, several transcription factors critical for pancreas development have been identified. Despite this success, many of the cell surface and extracellular factors necessary for proper islet morphogenesis and function remain uncharacterized. Previous studies have shown that transgenic over-expression of the transcription factor HNF6 specifically in the pancreatic endocrine cell lineage resulted in the disruption of islet morphogenesis, including dysfunctional endocrine cell sorting, increased islet size, and failure of islets to migrate away from the ductal epithelium. We exploited the dysmorphic islets in pdx1PBHnf6 animals as a tool to identify factors important for islet morphogenesis. Genome-wide microarray analysis was used to identify differences in the gene expression profiles of late gestation and early postnatal pancreas tissue from wild type and pdx1PBHnf6 animals. We report the identification of genes with an altered expression in HNF6 Tg animals and highlight factors with potential importance in islet morphogenesis.
Publication Title
Gene expression profiling of a mouse model of pancreatic islet dysmorphogenesis.
Sample Metadata Fields
Specimen part
View Samples