To define and compare the genome-wide transcriptional signatures of Notch1+ cells in intestinal tumors and in normal ISCs we performed Affymetrix analyses of these two populations.
Lineage tracing of Notch1-expressing cells in intestinal tumours reveals a distinct population of cancer stem cells.
Specimen part
View SamplesWe examined the kinetics of production of mRNAs and small RNAs derived from transposable elements during mouse spermatogenesis, in whole gonads of wildtype and DNA methylation-deficient males (Dnmt3L and Miwi2 mutants). We found that in absence of DNA methylation, transposon reactivation is not constitutive but rather occurs in a class- and development-specific manner : both the intensity of reactivation and the number of reactivated transposon classes increased as germ cells progress in meiosis. Moreover, we observed that transposon silencing before meiosis is not due to increased cleavage by the piRNA machinery. In contrast, the burst of transposon transcripts occurring at meiosis in the absence of DNA methylation serve as substrates for increased piRNA production Overall design: Six whole testis samples were analyzed, corresponding to three time points (16.5dpc, 10dpp and 20dpp) each for Dnamt3L-/- animals and control littermates. For 16.5dpc, testes from 7/8 mice were pooled per genotype. For the other stages, three mice were pooled per genotype.
DNA methylation restrains transposons from adopting a chromatin signature permissive for meiotic recombination.
No sample metadata fields
View SamplesTranscriptional analysis of human T cells differentiated in 4 T Helper context ( Th0, Th1, Th2 and Th17) in the presence or not of Interferon alpha
Combinatorial flexibility of cytokine function during human T helper cell differentiation.
Specimen part
View SamplesIntegration of multiple signals shapes cell adaptation to their microenvironment through synergistic and antagonistic interactions. The combinatorial complexity governing signal integration for multiple cellular output responses has not been resolved. For outputs measured in the conditions 0 (control), signals X, Y, X+Y, combinatorial analysis revealed 82 possible interaction profiles, which we biologically assimilated to 5 positive, and 5 negative interaction modes. To experimentally validate their use in living cells, we designed an original computational workflow, and applied it to transcriptomics data of innate immune cells integrating physiopathological signal combinations. Up to 9 of the 10 defined modes coexisted in context-dependent proportions. Each integration mode was enriched in specific molecular pathways, suggesting a coupling between genes involved in particular functions, and the corresponding mode of integration. We propose that multimodality and functional coupling are general principles underlying the systems level integration of physiopathological and pharmacological stimuli by mammalian cells.
Combinatorial code governing cellular responses to complex stimuli.
Time
View SamplesLong interspersed elements 1 (LINE-1 or L1) are retrotransposons that dominate the mouse genomic landscape, and are expressed in Embryonic Stem Cells (ESCs), germ cells, and during early development. Based on clear precedents in plants and fission yeast, we investigated in this study a role for RNAi and other RNA degradation pathways in the regulation of L1 expression and mobilization. We uncovered the existence of novel small (s)RNAs that map to active L1 elements. Some of these sRNAs have characteristics of cognate short-interfering RNA populations, while others display length heterogeneity that evokes a biogenesis through a RNA surveillance pathway, in a Dicer-independent manner. We additionally found that genetic ablation of Dicer and the sRNA effector protein AGO2 has complex and profound consequences on L1 transcription and mobilization in ESCs, indicating that endogenous RNA interference (RNAi) pathway indeed maintain genomic integrity against L1 proliferation. Finally, we investigated the implication of L1 retrotransposition during ESC differentiation and propose that the mobilization of L1 elements in Dicer mutant ESCs could partially explain the inability of these cells to differentiate. Overall design: 2 samples examined: WT E14 and Dicer mutant mouse ESCs
RNAi-dependent and independent control of LINE1 accumulation and mobility in mouse embryonic stem cells.
Specimen part, Subject
View SamplesXist is indispensable for X chromosome inactivation (XCI) in female mammalian cells. However, how Xist RNA directs chromosome-wide transcriptional inactivation of the X chromosome is largely unknown. Here, to study chromosome inactivation by Xist, we generated a system where ectopic Xist expression can be induced from several genomic contexts in aneuploid mouse ES cells. We found that ectopic Xist expression from any location on the X chromosome faithfully recapitulated endogenous XCI, showing the potency of Xist to initiate XCI. Genes that escape XCI remain consistently transcriptionally active upon ectopic XCI, regardless of their position relative to Xist transgenes, and the enrichment of CTCF at their promoters is implicated in directing XCI escape. Xist expression from autosomes facilitates their transcriptional silencing to different degrees, and gene density in proximity of the Xist transcription locus plays a central role in determining the efficiency of gene inactivation. We also show that the enrichment of LINE elements together with a specific chromatin environment facilitates Xist-mediated silencing of both X-linked and autosomal genes. These findings provide new insights into the epigenetic mechanisms that mediate XCI and identify genomic features that promote Xist-mediated chromosome-wide gene inactivation Overall design: 60 RNA-seq from mouse embryonic stem cells and fully differentiated neurons in which ectopic Xist epression is either triggered (plus samples) or not (minus samples) upon doxycycline treatment.
Genetic and epigenetic features direct differential efficiency of Xist-mediated silencing at X-chromosomal and autosomal locations.
Sex, Specimen part, Cell line, Subject
View SamplesHow the parental genomes of the very specialized sperm and oocyte cells are remodelled upon fertilization to confer totipotency has remained a tantalizing open questions. Indeed, in the case of mammals, the parental genomes undergo dramatic reprogramming upon fertilization, including differential dynamics of histone post-translational modifications. The roles of histone modifying enzymes in this process, which are maternally provided, are only just starting to emerge. Here, we explore the function of the oocyte inherited pool of Lsd1/Kdm1a, which encodes a histone H3K4 and K9 demethylase, during early mouse development. Maternal deficiency of Lsd1/Kdm1a results in developmental arrest by the two-cell stage, associated with dramatic and stepwise alterations in H3K9 and H3K4 methylation patterns depending on its demethylase activity. At the transcriptional level, two major changes occur. On one hand, switch from maternal-to-zygotic program fails to be induced. On the other hand, LINE-1 retrotransposons are not properly silenced, along with evidences for increased LINE-1 activity. We propose that Lsd1/Kdm1a is involved in the correct establishment of epigenetic information harboured by histones and is involved in the initiation of new pattern of genome expression driving early mouse development and preserving genome integrity Overall design: RNA-seq of invidual mouse two-cell stage embryos
Maternal LSD1/KDM1A is an essential regulator of chromatin and transcription landscapes during zygotic genome activation.
No sample metadata fields
View SamplesHow the parental genomes of the very specialized sperm and oocyte cells are remodelled upon fertilization to confer totipotency has remained a tantalizing open questions. Indeed, in the case of mammals, the parental genomes undergo dramatic reprogramming upon fertilization, including differential dynamics of histone post-translational modifications. The roles of histone modifying enzymes in this process, which are maternally provided, are only just starting to emerge. Here, we explore the function of the oocyte inherited pool of Lsd1/Kdm1a, which encodes a histone H3K4 and K9 demethylase, during early mouse development. Maternal deficiency of Lsd1/Kdm1a results in developmental arrest by the two-cell stage, associated with dramatic and stepwise alterations in H3K9 and H3K4 methylation patterns depending on its demethylase activity. At the transcriptional level, two major changes occur. On one hand, switch from maternal-to-zygotic program fails to be induced. On the other hand, LINE-1 retrotransposons are not properly silenced, along with evidences for increased LINE-1 activity. We propose that Lsd1/Kdm1a is involved in the correct establishment of epigenetic information harboured by histones and is involved in the initiation of new pattern of genome expression driving early mouse development and preserving genome integrity Overall design: RNA-seq of invidual mouse oocytes
Maternal LSD1/KDM1A is an essential regulator of chromatin and transcription landscapes during zygotic genome activation.
Cell line, Subject
View Samplesusing RNA-seq we characterized gene expression changes occuring upon knockout of BAP1, ASXL1, ASXL2, ASXL1/2 or Polycomb genes RING1B and EZH2. We also investigated the response to retinoic acid treatment in wild-type and BAP1 KO cells. Overall design: Examination of transcript abundance in wild-type HAP1 cells and in 9 different HAP1-mutated cell lines as well as upon retinoic acid treatment in wild-type and BAP1 KO cells. Two biological replicated were performed for each condition.
BAP1 complex promotes transcription by opposing PRC1-mediated H2A ubiquitylation.
Cell line, Treatment, Subject
View SamplesCharacterization of gene expression changes occuring upon knockout of RING1A, RING1B, and BAP1. Overall design: Four Samples
BAP1 complex promotes transcription by opposing PRC1-mediated H2A ubiquitylation.
Specimen part, Treatment, Subject
View Samples