O-GlcNAcylation is an essential, nutrient-sensitive post-translational modification, but its biochemical and phenotypic effects remain incompletely understood. To address this knowledge gap, we investigated the global transcriptional response to perturbations in O-GlcNAcylation. Unexpectedly, many transcriptional effects of O-GlcNAc transferase (OGT) inhibition were due to the activation of NRF2, the master regulator of redox stress tolerance. Moreover, we found that a signature of low OGT activity strongly correlates with NRF2 activation in multiple tumor expression datasets. Guided by this information, we identified KEAP1 (also known as KLHL19), the primary negative regulator of NRF2, as a direct substrate of OGT. We show that O-GlcNAcylation of KEAP1 at serine 104 is required for the efficient ubiquitination and degradation of NRF2. Interestingly, O-GlcNAc levels and NRF2 activation co-vary in response to glucose fluctuations, indicating that KEAP1 O-GlcNAcylation links nutrient sensing to downstream stress resistance. Our results reveal a novel regulatory connection between nutrient-sensitive glycosylation and NRF2 signaling, and provide a blueprint for future approaches to discover functionally important O-GlcNAcylation events on other KLHL family proteins in various experimental and disease contexts.
Glycosylation of KEAP1 links nutrient sensing to redox stress signaling.
Specimen part, Cell line
View SamplesGenome-wide transcriptome analyses have allowed for systems- level insights into gene regulatory networks. Due to the limited depth of quantitative proteomics, however, our understanding of post-transcriptional gene regulation and its effects on protein complex stoichiometry are lagging behind. Here, we employ deep sequencing and iTRAQ technology to determine transcript and protein expression changes of a Drosophila brain tumour model at near genome-wide resolution. In total, we quantify more than 6,200 tissue-specific proteins, corresponding to about 70% of all transcribed protein-coding genes. Using our integrated data set, we demonstrate that post-transcriptional gene regulation varies considerably with biological function and is surprisingly high for genes regulating transcription. We combine our quantitative data with protein-protein interaction data and show that post-transcriptional mechanisms significantly enhance co-regulation of protein complex subunits beyond transcriptional co-regulation. Interestingly, our results suggest that only about 11% of the annotated Drosophila protein complexes are co-regulated in the brain. Finally, we refine the composition of some of these core protein complexes by analysing the co-regulation of potential subunits. Our comprehensive transcriptome and proteome data provide a rich resource for quantitative biology and offer novel insights into understanding post- transcriptional gene regulation in a tumour model. Overall design: Transcriptomes of 1-3 day old adult female Drosophila melanogaster heads of control and brat mutant were generated by deep sequencing, in triplicate, using Illumina GAIIx.
Transcriptome and proteome quantification of a tumor model provides novel insights into post-transcriptional gene regulation.
Subject
View SamplesGray leaf spot (GLS) disease of maize can be caused by either of two sibling fungal species Cercospora zeina or Cercospora zeae-maydis. These species differ in geographical distribution, for example to date only C. zeina is associated with GLS in African countries, such as South Africa. Maize inbred line B73, which is susceptible to GLS, was planted in the field, and subjected to natural infection with C. zeina. Samples were collected from lower leaves with substantial GLS lesions and younger upper leaves of the same plants with very few immature GLS lesions. The first aim of the experiment was to determine which maize genes are induced in response to C. zeina infection. The second aim was to identify C. zeina genes expressed in planta during a compatible interaction. The third aim was to determine whether the C. zeina cercosporin biosynthetic (CTB) genes are expressed in planta. C. zeina fails to produce cercosporin in vitro in contrast to C. zeae-maydis. Cercosporin is a phytotoxin that is thought to play a role in pathogenicity of several Cercospora spp., however its role in the pathogenicity strategy of C. zeina is currently under investigation. Overall design: To collect material that reflected a difference between C. zeina infected B73 leaves and control B73 leaf material, samples were collected from two lower GLS infected leaves (second and third leaf internode below ear), and two upper leaves with minimal GLS symptoms (second and third internode above ear), respectively. The two lower leaves from each plant were pooled prior to RNA extraction, and the two upper leaves from each plant were pooled prior to RNA extraction. Upper and lower leaf samples from three maize B73 plants were subjected to RNA sequencing individually. The three maize plants were selected randomly as one plant per row from three rows of ten B73 plants each.
Complementation of CTB7 in the Maize Pathogen Cercospora zeina Overcomes the Lack of In Vitro Cercosporin Production.
Specimen part, Subject
View SamplesMYC-amplified medulloblastomas are highly lethal tumors. BET bromodomain inhibition was recently described to downregulate MYC-associated transcriptional activity in various cancer subtypes. To investigate whether JQ1, a BET bromodomain inhibitor is downregulation MYC and MYC-associated transcriptional activity, we performed global gene expression profiling of five medulloblastomas MYC-amplified patient-derived cell lines treated by JQ1 and the inactive form of JQ1.
BET bromodomain inhibition of MYC-amplified medulloblastoma.
Specimen part, Cell line, Treatment
View SamplesWe used microarrays to detail the global programme of gene expression after 4 months of TFEB overexpression in the brain.
Selective clearance of aberrant tau proteins and rescue of neurotoxicity by transcription factor EB.
Specimen part, Treatment
View SamplesWe discuss the use of pluripotent stem cell lines carrying fluorescent reporters driven by retinal promoters to derive three-dimensional (3-D) retina in culture and how this system can be exploited for elucidating human retinal biology, creating disease models in a dish, and designing targeted drug screens for retinal and macular degeneration. Furthermore, we realize that stem cell investigations are labor-intensive and require extensive resources. To expedite scientific discovery by sharing of resources and to avoid duplication of efforts, we propose the formation of a Retinal Stem Cell Consortium. In the field of vision, such collaborative approaches have been enormously successful in elucidating genetic susceptibility associated with age-related macular degeneration. Overall design: CRX+ flow sorted cells from human retina derived organoids were collected at 6 time points during differentiation (day (D) 37, 48, 67, 90, 134, 220).
Treatment Paradigms for Retinal and Macular Diseases Using 3-D Retina Cultures Derived From Human Reporter Pluripotent Stem Cell Lines.
Specimen part, Subject
View SamplesSenescence of stromal fibroblasts has been linked to establishment of cancer associated fibroblasts (CAF) and aging-associated increase of tumors. However, in clinically occurring carcinomas, density and proliferation of CAFs are frequently increased rather than decreased. We previously showed that genetic deletion or down-modulation of the canonical Notch effector CSL/RBP-J? in skin dermal fibroblasts is sufficient for CAF activation with consequent development of multifocal keratinocyte tumors. We now show that CSL deletion or knockdown induces senescence of primary fibroblasts derived from dermis, oral mucosa, breast and lung. CSL functions in these cells as a constitutive direct repressor of multiple senescence- and CAF-effector genes. At the same time, it physically interacts with p53, repressing its activity, and p53 activation provides a failsafe mechanism against compromised CSL function. Concomitant loss of CSL and p53 overcomes fibroblast senescence, enhances expression of CAF effector genes and, in vivo, promotes tumour and stromal cell expansion. Together, the findings support a CAF activation/stromal evolution model under convergent CSL/p53 control. Overall design: Human Dermal Fibroblasts were transfected with two different siRNA against CSL in parallel with a control siRNA. Total RNA was extracted 3 days post-transfection, followed by RNA-Seq analysis.
Combined CSL and p53 downregulation promotes cancer-associated fibroblast activation.
No sample metadata fields
View SamplesSenescence of stromal fibroblasts has been linked to establishment of cancer associated fibroblasts (CAF) and aging-associated increase of tumors. However, in clinically occurring carcinomas, density and proliferation of CAFs are frequently increased rather than decreased. We previously showed that genetic deletion or down-modulation of the canonical Notch effector CSL/RBP-J-kappa in skin dermal fibroblasts is sufficient for CAF activation with consequent development of multifocal keratinocyte tumors. We now show that CSL deletion or knockdown induces senescence of primary fibroblasts derived from dermis, oral mucosa, breast and lung. CSL functions in these cells as a constitutive direct repressor of multiple senescence- and CAF-effector genes. At the same time, it physically interacts with p53, repressing its activity, with p53 activation providing a failsafe mechanism against compromised CSL function. Concomitant loss of CSL and p53 overcomes fibroblasts senescence, enhances CAF effector gene expression and, in vivo, promotes stromal and cancer cell expansion. Together, these findings support a CAF activation/stromal evolution model under convergent CSL/p53 control.
Combined CSL and p53 downregulation promotes cancer-associated fibroblast activation.
Specimen part
View SamplesGoal of the analysis was to identify the mechansisms accounting fo the synergy of T cells redirected to the tumor associated large T antigen and T cells redirected to the Uty minor histocompatibility antigen
T Cells Redirected to a Minor Histocompatibility Antigen Instruct Intratumoral TNFα Expression and Empower Adoptive Cell Therapy for Solid Tumors.
Specimen part, Treatment
View SamplesPurpose: Zebrafish neurons regenerate from Müller glia following retinal lesions. Genes and signaling pathways important for retinal regeneration in zebrafish have been described, but our understanding of how Mu¨ller glial stem cell properties are regulated is incomplete. Mammalian Mu¨ller glia possess a latent neurogenic capacity that might be enhanced in regenerative therapies to treat degenerative retinal diseases. Methods: To identify transcriptional changes associated with stem cell properties in zebrafish Mu¨ller glia, we performed a comparative transcriptome analysis from isolated cells at 8 and 16 hours following an acute, photic lesion, prior to the asymmetric division that produces retinal progenitors. Results: We report a rapid, dynamic response of zebrafish Müller glia, characterized by activation of pathways related to stress, NF-kappa B signaling, cytokine signaling, immunity, prostaglandin metabolism, circadian rhythm, and pluripotency, and an initial repression of Wnt signaling. When we compared publicly available transcriptomes of isolated mouse Mu¨ller glia from two retinal degeneration models, we found that mouse Müller glia showed evidence of oxidative stress, variable responses associated with immune regulation, and repression of pathways associated with pluripotency, development, and proliferation. Conclusions: Categories of biological processes/pathways activated following photoreceptor loss in regeneration-competent zebrafish Mu¨ller glia, which distinguished them from mouse Mu¨ller glia in retinal degeneration models, included: cytokine signaling (notably NF-kappa B), prostaglandin E2 synthesis, expression of core clock genes, and pathways/metabolic states associated with pluripotency. These regulatory mechanisms are relatively unexplored as potential mediators of stem cell properties likely to be important in Müller glial cells for successful retinal regeneration. Overall design: Transcriptional profiles of 0, 8, and 16 hour post-lesion zebrafish Müller glia (in triplicate) were generated by high-throughput sequencing in an Illumina GAIIx.
Rapid, Dynamic Activation of Müller Glial Stem Cell Responses in Zebrafish.
No sample metadata fields
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