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GSE26600
Mus musculus
93 Downloadable Samples
Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
Methylazoxymethanol (MAM), the genotoxic metabolite of the cycad azoxyglucoside cycasin, induces genetic alterations in bacteria, yeast, plants, insects and mammalian cells, but adult nerve cells are thought to be unaffected. We show that the brains of young adult mice treated with a single systemic dose of MAM display DNA damage (O6-methylguanine lesions) that peaks at 48 hours and decline to near-normal levels at 7 days post-treatment. By contrast, at this time, MAM-treated mice lacking the gene encoding the DNA repair enzyme O6-methylguanine DNA methyltransferase (MGMT), showed persistent O6-methylguanine DNA damage. The DNA damage was linked to cell-signaling pathways that are perturbed in cancer and neurodegenerative disease. These data are consistent with the established carcinogenic and developmental neurotoxic properties of MAM in rodents, and they support the proposal that cancer and neurodegeneration share common signal transduction pathways. They also strengthen the hypothesis that early life exposure to the MAM glucoside cycasin has an etiological association with a declining, prototypical neurodegenerative disease seen in Guam, Japan, and New Guinea populations that formerly used the neurotoxic cycad plant for medicine and/or food. Exposure to environmental genotoxins may have relevance to the etiology of related tauopathies, notably, Alzheimers disease, as well as cancer.
Publication Title
The cycad genotoxin MAM modulates brain cellular pathways involved in neurodegenerative disease and cancer in a DNA damage-linked manner.
Sample Metadata Fields
Sex, Specimen part, Time
View Samples- Homo sapiens
- 12 Downloadable Samples
- Illumina HumanHT-12 V4.0 expression beadchip
Description
Huntingtons disease (HD) is an incurable hereditary neurodegenerative disorder, which manifests itself as a loss of GABAergic medium spiny (GABA MS) neurons in the striatum and caused by an expansion of the CAG repeat in exon 1 of the huntingtin gene. There is no cure for HD, existing pharmaceutical can only relieve its symptoms. Here, induced pluripotent stem cells were established from patients with low CAG repeat expansion in the huntingtin gene, and were then efficiently differentiated into GABA MS-like neurons under defined culture conditions. Analysis of differentially expressed genes between Huntingtons disease and wild type iPSCs derived GABA MS-like neurons has been performed.
Publication Title
Manifestation of Huntington's disease pathology in human induced pluripotent stem cell-derived neurons.
Sample Metadata Fields
Age, Specimen part
View Samples- Mus musculus
- 4 Downloadable Samples
- Affymetrix Mouse Gene 1.0 ST Array (mogene10st)
Description
Neural precursor cells (NPCs) in the mammalian neocortex generate various neuronal and glial cell types in a developmental stage-dependent manner. Most neocortical NPCs lose their neurogenic potential after birth. We have previously shown that high mobility group A (HMGA) proteins confer the neurogenic potential on early-stage NPCs during the midgestation period, although the underlying mechanisms are not fully understood. Here we performed microarray analysis and compared expression profiles between control and HMGA2-overexpressed NPCs.
Publication Title
IMP2 regulates differentiation potentials of mouse neocortical neural precursor cells.
Sample Metadata Fields
Specimen part
View Samples- Arabidopsis thaliana
- 2 Downloadable Samples
- Affymetrix Arabidopsis ATH1 Genome Array (ath1121501)
Description
Red light can affect a variety of responses in Arabidopsis. We characterize the early gene expression patterns of seedlings exposed to 1 hour of red light using a small sized sample of 5, 7-day-old seedlings and also performed dark controls.
Publication Title
Extraction and labeling methods for microarrays using small amounts of plant tissue.
Sample Metadata Fields
No sample metadata fields
View Samples- Danio rerio
- 14 Downloadable Samples
IlluminaHiSeq2000
Description
Purpose: The ability of adult zebrafish tissues to undergo dedifferentiation provides an opportunity to probe the molecular underpinnings of cell identity and reprogramming. Zebafish muscle regeneration utilizes dedifferentiation to reprogram mature multinucleated myocytes into dedifferentiated myoblast that re-enter the cell cycle. A unique advantage of this system is that the regenerating cell mass is large and fairly homogenous, facilitating genomics approaches to uncovering the underlying biology. Methods: To better understand cellular reprogramming of mature myocytes, we temporally analyzed the changing transcriptome leading up to the proliferative switch. RNA was obtained after Laser Micro-dissection (LMD) of Control, 9 hour post-injury (HPI) or 18 HPI using Trizol and micro column purification. Illumina''s TruSeq Stranded mRNA Library Prep Kit and 0.1 - 4 µg total mRNA from pooled purified RNA samples were used for performing ribosomal-depletion (Ribo-Zero Gold rRNA Removal Kit, Illumina) and library preparation. Sequencing was performed by the UM DNA Sequencing Core, using an Illumina Hi-Seq 2000 (50-cycle, single end read) platform. Results: Clustering and functional annotation of differentially expressed genes highlighted the importance of catabolic and phagocytic processes upregulation at 9 and 18 hours post injury (hpi). Furthermore, genes encoding principle regulators of chromatin states were actively re-regulated during the reprogramming process. Utilizing the accessibility of these tissues in the zebrafish model, kKnockdown experiments enabled in vivo validation and phenotypic analysis of candidate genes and pathways for their roles in genomic and cellular reprogramming. Additionally, we found that despite of their low expression levels, lncRNAs were highly represented in gene clusters with dynamic, “switch-like” expression profiles, and that miRNA processing was also found important for reprogramming Conclusions: We conclude that reprogramming of a “post-mitotic” myocyte into a dedifferentiated myoblast requires both heritable yet nuanced epigenetic alterations and molecular switches that involve transcription factors, miRNA and lncRNA, while maintaining the lineage restriction of the cell of origin. Overall design: Early time points post injury (9 & 18 hours) mRNA and lncRNA profiles of Zebrafish lateral eye muscle (EOM) were generated by deep sequencing, in quadruplicate, using Illumina Hi-seq.
Publication Title
Temporally distinct transcriptional regulation of myocyte dedifferentiation and Myofiber growth during muscle regeneration.
Sample Metadata Fields
No sample metadata fields
View Samples- Mus musculus
- 6 Downloadable Samples
- Affymetrix Mouse Genome 430 2.0 Array (mouse4302)
Description
Mutations of the transcriptional regulator Mecp2 cause the X-linked autism spectrum disorder Rett syndrome (RTT), and Mecp2 has been implicated in several other neurodevelopmental disorders. To identify potential target genes regulated directly or indirectly by MeCP2, we performed comparative gene expression analysis via oligonucleotide microarrays on Mecp2-/y (Mecp2-null) and wild-type CPN purified via fluorescence-activated cell sorting (FACS).
Publication Title
Reduction of aberrant NF-κB signalling ameliorates Rett syndrome phenotypes in Mecp2-null mice.
Sample Metadata Fields
Specimen part
View Samples- Arabidopsis thaliana
- 6 Downloadable Samples
- Affymetrix Arabidopsis ATH1 Genome Array (ath1121501)
Description
These investigations studied the fundamentals of how plants perceive gravity and develop in microgravity. It informs how gene regulation is altered by spaceflight conditions.
Publication Title
Comparative transcriptomics indicate changes in cell wall organization and stress response in seedlings during spaceflight.
Sample Metadata Fields
Specimen part
View Samples- Saccharomyces cerevisiae
- 4 Downloadable Samples
- Illumina Genome Analyzer IIx
Description
The recently proposed exozyme hypothesis posits that subunits of the RNA processing exosome assemble into structurally distinct protein complexes that function in disparate cellular compartments and RNA metabolic pathways. Here, in a genetic test of this hypothesis, we examine the role of Dis3 -- an essential polypeptide with endo- and 3'' to 5'' exo-ribonuclease activity -- in cell cycle progression. We present several lines of evidence that perturbation of DIS3 affects microtubule (MT) localization and structure in Saccharomyces cerevisiae. Cells with a DIS3 mutation: (i) accumulate anaphase and pre-anaphase mitotic spindles; (ii) exhibit spindles that are mis-oriented and displaced from the bud neck; (iii) harbor elongated spindle-associated astral MTs; (iv) have an increased G1 astral MT length and number; and (v) are hypersensitive to MT poisons. Mutations in the core exosome genes RRP4 and MTR3 and the exosome cofactor gene MTR4 -- but not other exosome subunit gene mutants -- also elicit MT phenotypes. RNA deep sequencing analysis (RNA-seq) shows broad changes in the levels of cell cycle- and microtubule-related transcripts in mutant strains. Collectively, the different mitotic phenotypes and distinct sets of mRNAs affected by the exosome subunit and cofactor mutants studied here suggest that Dis3 has a core exosome-independent role(s) in cell cycle progression. These observations are consistent with the predictions of the exozyme hypothesis and also suggest an evolutionarily conserved role for Dis3 in linking RNA metabolism, MTs, and mitotic progression. Overall design: RNA-seq analysis of total RNA harvested from WT, mtr3-1, mtr4-1, and Dis3^mtr (rrp44-1/mtr17-1) Saccharomyces cerevisiae strains after a temperature shift.
Publication Title
Pronounced and extensive microtubule defects in a Saccharomyces cerevisiae DIS3 mutant.
Sample Metadata Fields
Cell line, Treatment, Subject
View Samples- Mus musculus
- 157 Downloadable Samples
- Illumina HiSeq 1000
Description
Post-transcriptional regulation of cellular mRNA is essential for protein synthesis. Here we describe the importance of mRNA translational repression and mRNA subcellular location for protein expression during B lymphocyte activation and the DNA damage response. Cytoplasmic RNA granules are formed upon cell activation with mitogens, including stress granules that contain the RNA binding protein Tia1. Tia1 binds to a subset of transcripts involved in cell stress, including p53 mRNA, and controls translational silencing and RNA granule localization. DNA damage promotes mRNA relocation and translation in part due to dissociation of Tia1 from its mRNA targets. Upon DNA damage, p53 mRNA is released from stress granules and associates with polyribosomes to increase protein synthesis. Global analysis of cellular mRNA abundance and translation indicates that this is an extended ATM-dependent mechanism to increase protein expression of key modulators of the DNA damage response. Overall design: Splenic B cells from C57BL/6Babr mice were isolated and activated with LPS for 48 hours prior induction or not of DNA damage with etoposide. After 4 hours, cells were treated with cycloheximide (100 microgrames per ml) for 3 minutes. Then, cytoplasmic extracts were collected. Polysome fractionation in sucrose gradients (10-50% sucrose) was performed for isolation of mRNA associated to monosomes (fractions 4 to 7), light polysomes (fractions 8 to 10) or heavy polysomes (fractions 11 to 16). The ATM kinase inhibitor KU55933 was added 1 hour prior induction of DNA damage with etoposide.
Publication Title
Tia1 dependent regulation of mRNA subcellular location and translation controls p53 expression in B cells.
Sample Metadata Fields
Specimen part, Cell line, Subject
View Samples- Homo sapiens
- 13 Downloadable Samples
- Illumina Genome Analyzer IIx
Description
Crosslinking and immunoprecipitation (CLIP) is increasingly used to map transcriptome-wide binding sites of RNA-binding proteins (RBPs). We developed a method for CLIP data analysis and applied it to compare 254 nm CLIP with PAR-CLIP, which involves crosslinking of photoreactive nucleotides with 365 nm UV light. We found small differences in the accuracy of these methods in identifying binding sites of HuR, a protein that binds low-complexity sequences and Argonaute 2, which has a complex binding specificity. We show that crosslink-induced mutations lead to single-nucleotide resolution for both PAR-CLIP and CLIP. Our results confirm the expectation from original CLIP publications that RNA-binding proteins do not protect sufficiently their sites under the denaturing conditions used during the CLIP procedure, and we show that extensive digestion with sequence-specific ribonucleases strongly biases the set of recovered binding sites. We finally show that this bias can be substantially reduced by milder nuclease digestion conditions. Overall design: We performed duplicate experiments for each variant of the CLIP protocol (CLIP, PAR-CLIP), each protein (HuR, Ago2), and enzymatic digestion (complete T1 digestion, mild MNase digestion). In addition, we performed a single PAR-CLIP experiment with mild T1 digestion.
Publication Title
A quantitative analysis of CLIP methods for identifying binding sites of RNA-binding proteins.
Sample Metadata Fields
No sample metadata fields
View Samples