TERT is an essential protein component of telomerase, a ribonuclearprotein complex that protects chromosomal ends. Ectopic expression of TERT in mouse skin activates hair follicle stem cells and induces active growth phase of hair cycles, called anagen. This activity of TERT is independent of its reverse transcriptase function, indicating that this is a non-telomeric function of TERT.
TERT promotes epithelial proliferation through transcriptional control of a Myc- and Wnt-related developmental program.
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View SamplesMetazoans utilize a handful of highly conserved signaling pathways to create a signaling backbone that governs all stages of development, by providing spatial and temporal cues that influence gene expression. How these few signals have such a versatile developmental action is of significance to evolution, development, and disease. Their versatility likely depends upon the larger-scale network they form through integration. Such integration is exemplified by cross-talk between the Notch and the Receptor Tyrosine Kinase (RTK) pathways. We examined the transcriptional output of Notch-RTK cross-talk during Drosophila development and present in vivo data that supports a role for selected mutually-regulated genes as potentially important nodal points for signal integration. We find the complex interplay between these pathways involves their mutual regulation of numerous core components of RTK signaling in addition to targets that include components of all the major signalling pathways (TGF-, Hh, Jak/Stat, Nuclear Receptor and Wnt). Interestingly, Notch-RTK integration did not lead to general antagonism of either pathway, as is commonly believed. Instead, integration had a combinatorial effect on specific cross-regulated targets, which unexpectedly included the majority of Ras-responsive genes, suggesting Notch can specify the response to Ras activation.
Nodal points and complexity of Notch-Ras signal integration.
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View SamplesThe PR domain containing 1a, with ZNF domain factor, gene prdm1a plays an integral role in the development of a number of different cell types during vertebrate embryogenesis, including neural crest cells, Rohon-Beard (RB) sensory neurons and the cranial neural crest-derived craniofacial skeletal elements. To better understand how Prdm1a regulates the development of various cell types in zebrafish, we performed a microarray analysis comparing wild type and prdm1a mutant embryos and identified a number of genes with altered expression in the absence of prdm1a. Rescue analysis determined that two of these, sox10 and islet1, lie downstream of Prdm1a in the development of neural crest cells and Rohon-Beard neurons, respectively. In addition, we identified a number of other novel downstream targets of Prdm1a that may be important for the development of diverse tissues during zebrafish embryogenesis.
prdm1a Regulates sox10 and islet1 in the development of neural crest and Rohon-Beard sensory neurons.
Age, Specimen part
View Samples5 day RNAi treatment to knockdown Enigma, CG9006, a Drosophila mitochondrial protein with homology to acyl-CoA dehydrogenases.
Enigma, a mitochondrial protein affecting lifespan and oxidative stress response in Drosophila.
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View SamplesThe recent identification of novel progenitor populations that contribute to the developing heart in a distinct temporal and spatial manner has fundamentally improved our understanding of cardiac development. However, little remains known about cardiac specification events prior to the establishment of the heart tube, or the mechanisms that direct atrial versus ventricular specification. We have identified a novel progenitor population that gives rise specifically to cardiovascular cells of the ventricles but not the atria, and to the epicardium of the differentiated heart. We determined that this cell population is first specified during gastrulation, when it transiently expresses Foxa2, a gene not previously implicated in cardiac development. Using chimeric mosaic analysis we further demonstrate that Foxa2 is cell-autonomously required for the development of ventricular cells. Finally, we reveal the existence of an analogous Foxa2+ cardiac mesoderm population during in vitro differentiation from embryonic stem cells and illustrate that these cells express genes relevant for heart development. Our data thus describe the first progenitor population identified as early as gastrulation that displays ventricular-specific differentiation potential. Together, these findings provide important new insights into the developmental origin of ventricular and atrial myocytes, and will lead to the establishment of new strategies for generating these cell types from pluripotent stem cells. Overall design: Examination of global gene expression in four different cell types
Foxa2 identifies a cardiac progenitor population with ventricular differentiation potential.
Specimen part, Subject
View SamplesHuman T-lymphotropic virus type 1 (HTLV-1) is associated with the development of Adult T-cell Leukemia, an aggressive CD4+ T-cells malignancy. Here, we have developed a new procedure to infect humanized mice with proviruses displaying specific mutations, such as one leading to the loss of the PDZ domain-binding motif (PBM) of Tax. In order to specifically analyze the in vivo role of the PBM of Tax, a comparative study of infected hu-mice was performed. We used next-generation sequencing to perform genome-wide transcriptomic analysis of T-cells infected with wild-type HTLV-1 virus or with virus bearing a mutated form of Tax lacking the PBM. Our results suggest that Tax PBM might be involved in the regulation of genes implicated in proliferation, apoptosis and cytoskeleton organization. Overall design: mRNA profiles of T-cells obtained from hu-Mice infected with wild-type or Tax-PBM HTLV-1 were generated by deep-sequencing in triplicates using Illumina's Hiseq3000 platform.
PDZ domain-binding motif of Tax sustains T-cell proliferation in HTLV-1-infected humanized mice.
Specimen part, Subject
View SamplesAdult neurogenesis in the murine dentate gyrus occurs in a specialized microenvironment that sustains the generation of neurons during life. To fully understand adult neurogenesis, it is essential to determine the neural stem cell (NSC) and progenitor developmental stages, their molecular determinants, and the niche cellular and molecular composition. We report on a single cell RNA sequencing study of the hippocampal niche, performed by isolating all the non-neuronal cell populations. Our analysis provides a comprehensive description of the dentate gyrus cells and allows the identification of exclusive cell type-specific markers. We define the developmental stages and transcriptional dynamics of NSCs and progenitors, and find that while NSCs represent a heterogeneous cellular continuum, progenitors can be grouped in distinct subtypes. We determine the oligodendrocyte lineage and transcriptional dynamics, and describe microglia transcriptional profile and activation state. The combined data constitutes a valuable resource to understand regulatory mechanisms of adult neurogenesis. Overall design: We generated transciptome data from cells unbiasely sorted from the hippocampal neurogenic niche after depleting the neuronal population
A Single-Cell RNA Sequencing Study Reveals Cellular and Molecular Dynamics of the Hippocampal Neurogenic Niche.
Specimen part, Cell line, Subject
View SamplesPurpose: The goal of this study is to compare the transcriptome profilling (RNA-seq) of inflorescences infected with tobacco ratle virus (TRV) to mock inoculated inflorescences (negative controls), in Arabidopsis plants Methods: Inflorescences of systemically TRV infected or mock-inoculated plants were collected from more than 40 independent Arabidopsis plants, at 14 days post-inoculation (dpi). TRV and mock mRNA profiles were generated by deep sequencing by Illumina HiSeq 2000. The sequence reads that passed quality filters (SOAPnuke) were analysed by Burrows-Wheeler (BWA) followed by ANOVA (ANOVA) and TopHat followed by Cufflinks. Genes and isoforms were quantified by RSEM sofware package. qRT-PCR validation was performed using TaqMan and SYBR Green assays. Results: Here we report a significant repression of DNA methylation genes in inflorescences of Arabidopsis plants infected with Tobacco rattle virus (TRV) that coincides with dynamic changes in methylation at the whole genome level. Arabidopsis mutants deficient in DNA methylation were more resistant to this virus in early colonized tissues but more susceptible at later time points of infection, indicating that DNA methylation was critical to control both proliferation and antiviral defense. We found that TRV interference with DNA methylation leads to changes in the methylation and trancriptional status of transposable elements (TEs), including TEs located in the promoter of disease resistance genes that were significantly repressed in plants exposed to TRV. Activation of both TEs and their nearby disease resistance genes was altered in a range of hypo- and hyper-methylated Arabidopsis mutants, indicating that perturbations in DNA methylation contributes to modulate their expression in infected plants. Conclussion: Our study showed that TRV interferes with DNA methylation to alter the transcriptional silencing of TEs, which in turn compromises the expression of neighboring disease resistance genes. Overall design: TRV and mock mRNA profiles were generated from Arabidopsis inflorescences by deep sequencing with Illumina HiSeq 2000.
Crosstalk between epigenetic silencing and infection by tobacco rattle virus in Arabidopsis.
Specimen part, Subject
View SamplesThe histone methyltransferase mixed lineage leukemia (MLL) is essential to maintain hematopoietic stem cells and is a leukemia protooncogene. Although Hox genes are well-characterized targets of MLL and MLL fusion oncoproteins, the range of Mll-regulated genes in normal hematopoietic cells remains unknown. Here we identify and characterize part of the Mll-transcriptional network in hematopoietic stem cells with an integrated approach by using conditional loss-of-function models, genomewide expression analyses, chromatin immunoprecipitation, and functional rescue assays. The Mll-dependent transcriptional network extends well beyond the previously appreciated Hox targets, is comprised of many characterized regulators of self-renewal, and contains target genes that are both dependent and independent of the MLL cofactor, Menin. Interestingly, Prdm16 emerged as a target gene that is uniquely effective at partially rescuing Mll-deficient hematopoietic stem and progenitor cells. This work highlights the tissue-specific nature of regulatory networks under the control of MLL/Trithorax family members and provides insight into the distinctions between the participation of MLL in normal hematopoiesis and in leukemia.
An MLL-dependent network sustains hematopoiesis.
Specimen part
View SamplesWe identified a subset of hepatocytes with high Telomerase Reverse transcriptase (Tert) that functions as the repopulating stem cells in homeostasis and injury. We performed RNA-Seq to reveal the differences of these cells and the other hepatocytes. Overall design: RNA mRNA profiles of TERT(High) and TERT (Low) hepatocytes from 2-month old mice were generated by deep sequencing, in triplicate, using Illumina platform.
Distributed hepatocytes expressing telomerase repopulate the liver in homeostasis and injury.
Age, Specimen part, Cell line, Subject
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