Plant reproduction depends on the concerted activation of many genes to assure the correct communication between pollen and pistil. Here we queried the whole transcriptome of Arabidopsis thaliana in order to identify genes with specific reproductive functions.
Whole genome analysis of gene expression reveals coordinated activation of signaling and metabolic pathways during pollen-pistil interactions in Arabidopsis.
Specimen part
View SamplesDespite their different origin and function, both pollen tubes and root hairs share the same sort of apical growth mechanism, i.e., the spatially focused cell expansion at the very apex. Ion fluxes, membrane trafficking, the actin cytoskeleton and their interconnection via signaling networks have been identified as fundamental processes underlying this kind of growth. Several molecules involved in apical growth have been identified, but the genetic basis is far from being fully characterized. We have used Affymetrix Arabidopsis ATH1 GeneChips to obtain the expression profiles of isolated Arabidopsis root hairs. A comparison with the expression profile of flow-sorted pollen grains reveals an overlap in the expression of 4989 genes, which corresponds to 42% of the root hair transcriptome and 76% of the pollen transcriptome, respectively. Our comparison with transcriptional profiles of vegetative tissues by principal component analysis and hierarchical clustering shows a clear separation of these samples comprised of cell types with diffuse growth from the two cell types with apical growth. 277 genes are enriched and 49 selectively expressed, respectively, in root hairs and pollen. From this set of genes emerges an apical growth signature containing novel candidate genes for apical growth determination.
Transcriptional profiling of Arabidopsis root hairs and pollen defines an apical cell growth signature.
Specimen part
View SamplesOn triggering of the T cell receptor CD8 T lymphocytes downregulate expression of the transcription factor KLF2. KLF2 expression remains low as these cells differentiate to Cytotoxic T lymphocytes (CTL) but may be re-expressed depending on the local environmental signals.
The impact of KLF2 modulation on the transcriptional program and function of CD8 T cells.
Specimen part
View SamplesThe present study reports an unbiased analysis of the cytotoxic T cell serine-threonine phosphoproteome using high resolution mass spectrometry. Approximately 2,000 phosphorylations were identified in CTLs of which approximately 450 were controlled by TCR signaling. A significantly overrepresented group of molecules identified in the phosphoproteomic screen were transcription activators, co-repressors and chromatin regulators. A focus on the chromatin regulators revealed that CTLs have high expression of the histone deacetylase HDAC7 but continually phosphorylate and export this transcriptional repressor from the nucleus. HDAC7 dephosphorylation results in its nuclear accumulation and suppressed expression of genes encoding key cytokines, cytokine receptors and adhesion molecules that determine CTL function. The screening of the CTL phosphoproteome thus reveals intrinsic pathways of serine-threonine phosphorylation that target chromatin regulators in CTLs and determine the CTL functional program. We used Affymetrix microarray analysis to explore the molecular basis for the role of HDAC7 in CTLs and the impact of GFP-HDAC7 phosphorylation deficient mutant expression on the CTL transcriptional profile.
Phosphoproteomic analysis reveals an intrinsic pathway for the regulation of histone deacetylase 7 that controls the function of cytotoxic T lymphocytes.
Specimen part
View SamplesComparison of transcriptional profile of TCR stimulated P14-TCR wild-type and P14-PKD2 null murine lymph node cells
Protein kinase D2 has a restricted but critical role in T-cell antigen receptor signalling in mature T-cells.
Specimen part
View SamplesIn cytotoxic T cells (CTL), Protein Kinase B /Akt is activated by the T cell antigen receptor (TCR) and the cytokine Interleukin 2 (IL2), in part by phosophorylation of Akt by Phospholipid dependent kinase 1 (PDK1).
Protein kinase B controls transcriptional programs that direct cytotoxic T cell fate but is dispensable for T cell metabolism.
Specimen part
View SamplesThe aim of this study consists in detecting genes regulated by N-myc in the murine cochlea
Otx2 is a target of N-myc and acts as a suppressor of sensory development in the mammalian cochlea.
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View SamplesObjective: In idiopathic inflammatory myopathies (IIM) infiltration of immune cells into muscle and upregulation of MHC-I expression implies increased antigen presentation and involvement of the proteasome system. To decipher the role of immunoproteasomes in myositis, we investigated individual cell types and muscle tissues and focused on possible immune triggers. Methods: Expression of constitutive (PSMB5, -6, -7) and corresponding immunoproteasomal subunits (PSMB8, -9, -10) was analyzed by real-time RT-PCR in muscle biopsies and sorted peripheral blood cells of patients with IIM, non-inflammatory myopathies (NIM) and healthy donors (HD). Protein analysis in muscle biopsies was performed by western blot. Affymetrix HG-U133 platform derived transcriptome data from biopsies of different muscle diseases and from immune cell types as well as monocyte stimulation experiments were used for validation, coregulation and coexpression analyses. Results: Real-time RT-PCR revealed significantly increased expression of immunoproteasomal subunits (PSMB8/-9/-10) in DC, monocytes and CD8+ T-cells in IIM. In muscle biopsies, the immunosubunits were elevated in IIM compared to NIM and exceeded levels of matched blood samples. Proteins of PSMB8 and -9 were found only in IIM but not NIM muscle biopsies. Reanalysis of 78 myositis and 20 healthy muscle transcriptomes confirmed these results and revealed involvement of the antigen processing and presentation pathway. Comparison with reference profiles of sorted immune cells and healthy muscle confirmed upregulation of PSMB8 and -9 in myositis biopsies beyond infiltration related changes. This upregulation correlated highest with STAT1, IRF1 and IFN expression. Elevation of T-cell specific transcripts in active IIM muscles was accompanied by increased expression of DC and monocyte marker genes and thus reflects the cell type specific involvement observed in peripheral blood. Conclusions: Immunoproteasomes seem to indicate IIM activity and suggest that dominant involvement of antigen processing and presentation may qualify these diseases exemplarily for the evolving therapeutic concepts of immunoproteasome specific inhibition.
Upregulation of immunoproteasome subunits in myositis indicates active inflammation with involvement of antigen presenting cells, CD8 T-cells and IFNΓ.
Specimen part
View SamplesMetastasis of human tumours to LNs is a universally negative prognostic factor. LN stromal cells (SCs) play a crucial role in enabling T cell responses, and since tumour metastases modulate their structure and function, this interaction may suppress immune responses to tumour antigens. However the SC subpopulations that respond to infiltration of malignant cells into human LNs have not been defined. Using microarray, we sought to assess gene expression profiles of two distinct SC subpopulations isolated from melanoma-infiltrated LNs.
Distinctive Subpopulations of Stromal Cells Are Present in Human Lymph Nodes Infiltrated with Melanoma.
Specimen part
View SamplesThe maintenance of the TFH phenotype depends on continuous signals via ICOS. For a global assessment of differences in gene expression after interruption of the ICOS pathway a genome wide transcriptome analysis was performed. We used the OT-II adoptive transfer system to isolate antigen-specific TFH cells (day 6 after immunization) after short-term (6 hours) blockade of the ICOS pathway using a monoclonal antibody against ICOS-L.
ICOS maintains the T follicular helper cell phenotype by down-regulating Krüppel-like factor 2.
Sex, Specimen part, Treatment
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