The origin of humans was accompanied by the emergence of new behavioral and cognitive functions, including language and specialized forms of abstract representation. However, the molecular foundations of these human capabilities are poorly understood. Because of the extensive similarity between human and chimpanzee DNA sequences, it has been suggested that many of the key phenotypic differences between species result primarily from alterations in the regulation of genes rather than in their sequences.
Elevated gene expression levels distinguish human from non-human primate brains.
Sex, Age, Specimen part
View SamplesGene expression changes in mouse skeletal muscle were assessed in wild-type and Jhdm2a null skeletal muscle in an effort to define the role of Jhdm2a in energy expenditure and metabolism.
Role of Jhdm2a in regulating metabolic gene expression and obesity resistance.
Sex, Age, Specimen part
View SamplesPolycomb group (PcG) proteins control organism development by regulating the expression of developmental genes. Transcriptional regulation by PcG proteins is achieved at least partly through the PRC2-mediated methylation on lysine 27 of histone H3 (H3K27) and PRC1-mediated ubiquitylation on lysine 119 of histone H2A (uH2A). As an integral component of PRC1, Bmi1 has been demonstrated to be critical for H2A ubiquitylation. Although recent studies have revealed the genome wide binding patterns of some of the PRC1 and PRC2 components, as well as the H3K27me3 mark, there have been no reports describing genome wide localization of uH2A. Using the recently developed ChIP-Seq technology, here we report genome wide localization of the Bmi1-dependent uH2A mark in MEF cells. Gene promoter averaging analysis indicates a peak of uH2A just inside the transcription start site (TSS) of well annotated genes. This peak is enriched at promoters containing the H3K27me3 mark and represents the least expressed genes in WT MEF cells. In addition, peak finding reveals regions of local uH2A enrichment throughout the mouse genome, including almost 700 gene promoters. Genes with promoter peaks of uH2A exhibit lower level expression when compared to genes that do not contain promoter peaks of uH2A. Moreover, we demonstrate that genes with uH2A peaks have increased expression upon Bmi1 knockout. Importantly, local enrichment of uH2A is not limited to regions containing the H3K27me3 mark. We provide evidence to suggest that DNA methylation is tightly linked to H2A ubiquitylation in high density CpG promoters. Thus, our work not only reveals Bmi1-dependent H2A ubiquitylation but also suggests that uH2A targeting in differentiated cells may employ a different mechanism from that in ES cells.
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Sex
View SamplesWound healing is an essential homeostatic mechanism that maintains the epithelial barrier integrity after tissue damage. Although we know the main events participating in the healing of a wound, many of the underlying molecular mechanisms remain unclear. Genetically amenable systems, such as wound healing in Drosophila imaginal discs, do not model all aspects of the repair process, but allow exploring many unanswered features of the healing response; e.g., which are the signal(s) responsible for initiating tissue remodeling? How is the sealing of the epithelia achieved? Or which are the inhibitory cues that cancel the healing machinery upon completion? Answering these and other questions demands in first place the identification and functional analysis of wound-specific genes. A variety of different microarray analyses of murine and humans have identified characteristic profiles of gene expression at the wound site, however, very few functional studies in healing regulation have been carried out. We developed an experimentally controlled method to culture imaginal discs that allows live imaging and biochemical analysis and is healing-permissive. Employing this approach, we performed a comparative genome-wide profiling between those Drosophila imaginal cells actively involved in healing versus their non-engaged siblings. This lets us identify a set of potential wound-specific genes. Importantly, besides identifying and categorizing new genes, we functionally tested many of their gene products by genetic interference and overexpression in a healing assay. This non-saturated analysis defines a relevant set of new genes whose changes in expression levels are functionally significant for proper tissue repair. There is promise that our newly identified wound-healing genes will guide future work in the more complex mammalian wound response.
Identification and functional analysis of healing regulators in Drosophila.
Specimen part, Treatment
View SamplesTranscription factor induced reprogramming of one specialized cell type into another is a promising approach for regenerative medicine. However, the process still remains poorly understood, in large part because of the lack of adequate experimental models. Here we describe a robust cell reprogramming system consisting of a B cell line with an inducible form of C/EBPa that can be converted into macrophages with essentially 100% efficiency in only 2 to 3 days. The conversion involves reciprocal changes in cell surface antigen expression, increase in cell granularity and size, alterations in cellular structures, formation of membrane extensions, acquisition of phagocytic capacity and an increased inflammatory responsiveness as well as migratory activity. Analysis of the transcriptome shows complex reciprocal regulation of B cell and macrophage genes, including transcription factors required for the formation of the two lineages. The fact that the cells become irreversibly committed to a macrophage fate within 1 to 2 days after activation of C/EBPa show that they are truly reprogrammed. The system should be useful to study epigenetic and cell biological mechanisms of transcription factor induced cell reprogramming.
A robust and highly efficient immune cell reprogramming system.
Cell line
View SamplesTEC (B6 vs Aire KO). Thymic epithelial cells from B6 strain and AIRE KO are compared.
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View SamplesMTCH2-mediated mitochondrial fusion drives exit from naive pluripotency in embryonic stem cells
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Sex, Specimen part, Cell line
View SamplesWe aimed to identify specific biomarkers of IFN-beta bioactivity in order to compare their gene expression induction by type I IFNs with the MxA, and to investigate their potential role in MS pathogenesis. Gene expression microarrays were performed in PBMC from MS patients who developed neutralizing antibodies (NAB) to IFN-beta. Nine genes followed patterns in gene expression over time similar to the MX1 and were selected for further experiments: IFI6, IFI27, IFI44L, IFIT1, HERC5, LY6E, RSAD2, SIGLEC1, and USP18. In vitro experiments revealed specific induction of selected biomarkers by IFN-beta but not IFN-gamma, and several markers, in particular USP18 and HERC5, were significantly induced at lower IFN-beta concentrations and more selective than the MX1 as biomarkers of IFN-beta bioactivity. In addition, USP18 expression was deficient in MS patients compared with healthy controls (p=0.0004). We propose specific biomarkers that may be considered in addition to the MxA to evaluate IFN-beta bioactivity, and to further explore their implication in MS pathogenesis.
Search for specific biomarkers of IFNβ bioactivity in patients with multiple sclerosis.
Sex, Age, Specimen part, Disease, Disease stage, Treatment, Subject, Time
View SamplesVaccination with naked DNA encoding myelin basic protein represents a promising therapeutic strategy in multiple sclerosis (MS). In this study, we assessed the potential of vaccination with a DNA construct coding for the myelin oligodendrocyte glycoprotein (MOG), an important candidate autoantigen in MS, to induce tolerance and protect against experimental autoimmune encephalomyelitis (EAE). Herein, we demonstrated that MOG-DNA vaccination reduced the clinical and histopathological signs of EAE when administered in both prophylactic and therapeutic settings. Further mechanistic experiments revealed that the protective effects of MOG-DNA vaccines were associated with a reduction of antigen-specific Th1 and Th17 cellular immune responses and expansion of regulatory T cells in periphery, and up-regulation in the central nervous system of genes encoding neurotrophic factors and proteins involved in remyelination. These results may set the rationale for the use of MOG-based DNA vaccines to induce tolerance in MS patients.
No associated publication
Specimen part, Treatment
View SamplesA genome-wide map of circular RNA in adult zebrafish.
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