Depolarization of resting membrane potential in select cells in Xenopus larvae induces striking hyperpigmentation due to dysregulation of melanocytes. Here, we show that this non-cell-autonomous process is mediated by cAMP, CREB, and the transcription factors Sox10 and Slug. Our microarray analysis reveals specific transcripts responsive to Vmem levels within a few hours of depolarization, and a set of 517 transcripts whose expression remains altered during the full hyperpigmented phenotype over a week later, linking instructor cell-depolarization to a range of developmental processes and disease states. We also show that voltage-dependent conversion of melanocytes involves the MSH-secreting melanotrope cells of the pituitary, and formulate a model for the molecular pathway linking the bioelectric properties of melanocyte cells microenvironment in vivo to the genetic and cellular changes induced in this melanoma-like phenotype. Remarkably, the phenotype is all-or-none: each individual animal either undergoes melanocyte conversion or not, as a whole. This group decision is stochastic, resulting in varying percentages of hyperpigmented individuals for a given experimental treatment. To understand the stochasticity and dynamic properties of this complex signaling system, we developed a novel computational method that automates the reverse-engineering of stochastic dynamic signaling models. We used this method to discover a network model that quantitatively explained our complex dataset, and even made correct predictions for new experiments that we validated in vivo. Taken together, these data (1) reveal new molecular details about a novel trigger of metastatic-like developmental cell behavior in vivo, (2) suggest new targets for biomedical intervention, and (3) demonstrate proof-of-principle of a computational method for understanding stochastic decision-making by cells during embryonic development and metastasis.
Serotonergic regulation of melanocyte conversion: A bioelectrically regulated network for stochastic all-or-none hyperpigmentation.
Specimen part
View SamplesMissense mutations in the gene for the ubiquitously expressed superoxide dismutase-1 (SOD1) are one of the causes of familial amyotrophic lateral sclerosis (ALS), the most common adult onset motor neuron disease in humans killing selectively large motor neurons. Mice and rats overexpressing mutant SOD1 develop an adult onset neurodegenerative disease with hindlimb-paralysis and subsequent death similar to the human condition. In order to analyze the effects of mutant SOD1 expression onto the most affected cell-type in ALS, a small subpopulation of spinal cord cells, we propose to use laser microdissection to isolate mouse lumbar motor neurons and to assess the changes onto the mRNA expression profile using Affymetrix GeneChips compared to control animals. While two studies applying a genomic approach on the ALS mouse models used the entire spinal cord, contributions of changes to motor neurons were masked by the inflammatory effects of mutant SOD1 and the much larger population of non-motor neuronal cells. What is therefore needed is a cell-type specific expression profile that could reveal dysregulations in the transcriptome of the affected motor neurons.
Toxicity from different SOD1 mutants dysregulates the complement system and the neuronal regenerative response in ALS motor neurons.
No sample metadata fields
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Serially transplantable mammary epithelial cells express the Thy-1 antigen.
Specimen part
View SamplesEnriched cell populations from murine mammary epithelium were isolated by FACS and subjected to Affymetrix Mouse 430 2.0 microarray analysis.
Serially transplantable mammary epithelial cells express the Thy-1 antigen.
Specimen part
View SamplesEnriched cell populations from murine mammary epithelium were isolated by FACS and subjected to Affymetrix Mouse 430 2.0 microarray analysis.
Serially transplantable mammary epithelial cells express the Thy-1 antigen.
Specimen part
View SamplesThe adenosine 2A receptor (A2AR) is expressed on regulatory T cells (Tregs), but the functional significance is currently unknown. We compared the gene expression between wild-type (WT) and A2AR knockout (KO) Tregs and between WT Tregs treated with vehicle or a selective A2AR agonist.
Autocrine adenosine signaling promotes regulatory T cell-mediated renal protection.
Specimen part
View SamplesBy sequencing 36 cDNA libraries with Illumina technology, we identified genes differentially expressed in soybean plants in response to water deficit and genes that were either up- or down-regulated in different periods of the day. Of 54,175 predicted soybean genes (Glyma v1.1), 35.52% exhibited expression oscillations in a 24 h period. This number increased to 39.23% when plants were submitted to water deficit. Major differences in gene expression were observed in the control plants from late day (ZT16) until predawn (ZT20) periods, indicating that gene expression oscillates during the course of 24 h in normal development. Under water deficit, dissimilarity increased in all time-periods, indicating that the applied stress influenced gene expression. Results suggest that time of day, as well as light and temperature oscillations that occur considerably affect the regulation of water deficit stress response in soybean plants. Overall design: Gene expression analysis of soybean leaves under water deficit in 6 periods of day by sequencing 36 libraries, in triplicate, in Illumina platform.
Daytime soybean transcriptome fluctuations during water deficit stress.
Specimen part, Subject
View SamplesIsolation of cell populations is untangling complex biological interactions, but studies comparing methodologies lack in vivo complexity and draw limited conclusions about the types of transcripts identified by each technique. Furthermore, few studies compare FACS-based techniques to ribosomal affinity purification, and none do so genome-wide. We addressed this gap by systematically comparing nuclear-FACS, whole cell-FACS, and RiboTag affinity purification in the context of D1 or D2 dopamine receptor-expressing medium spiny neuron (MSN) subtypes of the nucleus accumbens (NAc), a key brain reward region. We find that nuclear-FACS-seq generates a substantially longer list of differentially expressed genes between these cell types, and a significantly larger number of neuropsychiatric GWAS hits than the other two methods. RiboTag-seq has much lower coverage of the transcriptome than the other methods, but very efficiently distinguishes D1- and D2-MSNs. We also demonstrate differences between D1- and D2-MSNs with respect to RNA localization, suggesting fundamental cell type differences in mechanisms of transcriptional regulation and subcellular transport of RNAs. Together, these findings guide the field in selecting the RNAseq method that best suits the scientific questions under investigation. Overall design: Forty-nine samples constituting 39 samples from male mice: 16 whole cell-FACS (D1 n=9, D2 n=7), 11 nuclear-FACS (D1 n=6, D2 n=5), and 12 RiboTag (D1 n=6, D2 n=6), and 10 samples from female mice (D1 n=5, D2 n=5).
Biology and Bias in Cell Type-Specific RNAseq of Nucleus Accumbens Medium Spiny Neurons.
Specimen part, Cell line, Subject
View SamplesThe c-MYC oncogene is a key transcription factor deregulated in most human tumors. Histone marks associated with transcriptionally active genes in euchromatic islands define the set of high-affinity c-MYC targets. The mechanisms involved in their recognition by c-MYC are not known but likely involve chromatin-remodelling and chromatin-modifying complexes. Here, we show that c-MYC interacts with BPTF, a core subunit of the NURF complex that binds active chromatin. BPTF is required for the activation of the full c-MYC transcriptional programme in fibroblasts. BPTF knockdown leads to a decrease in c-MYC recruitment to DNA and to changes in chromatin accessibility. Using BPTF-null MEFs we show that BPTF is necessary for c-MYC-driven proliferation, G1-S progression, and replication stress, but not for c-MYC-driven apoptosis. Consistently, BPTF is required for the proliferation of cells driven by c-MYC, such as Burkitt lymphoma, and its expression in human cancer lines correlates with the activation of c-MYC gene signatures. Our findings point to the c-MYC-BPTF axis as a potential therapeutic target in cancer. Overall design: To assess whether BPTF is required for the transcriptional activity of c-MYC, human foreskin fibroblasts (HFF) were stably transduced with the chimeric MYC-ER cDNA (HFF MYC-ER) and infected with lentiviruses coding for either control (shNt) or BPTF-targeting shRNAs. Cells were serum-starved for 2 days to achieve quiescence and then treated with 4-hydroxytamoxifen (4-OHT)
BPTF is required for c-MYC transcriptional activity and in vivo tumorigenesis.
No sample metadata fields
View SamplesOrnithine decarboxylase is sufficient for prostate tumorigenesis via androgen receptor signaling
Ornithine Decarboxylase Is Sufficient for Prostate Tumorigenesis via Androgen Receptor Signaling.
No sample metadata fields
View Samples