ERa is essential for the anti-proliferative response of breast cancer cells not only to estrogen antagonists, but also to estrogen withdrawal by means of aromatase inhibitors. We explored here one of the simplest explanation for this, consisting in the possibility that ERa may have a wide genomic function in absence of ligands. The genomic binding of ERa in the complete absence of estrogen was then studied using hormone-dependent MCF7 cells, by chromatin immunoprecipitation sequencing. From these data, 4.2K highly significant binding events were identified, which were further confirmed by comparing binding events in cells expressing ERa to cells silenced for ERa. Apo-ERa binding sites were distributed close to genes with functions associated to cell growth and epithelial maintenance and show significant overlap with binding of other transcription factors important for luminal epithelial breast cancer. Interestingly, we found that upon ERa silencing cognate gene transcription in absence of estrogen is downregulated and this is accompanied by increased H27Kme3 at ERa binding sites. RNA-Seq experiments showed that unliganded ERa controls basal transcription widely, including both coding and noncoding transcripts. Genes affected by ERa silencing can be easily functionally related to mammary epithelium differentiation and maintenance, especially when considering downregulated genes. Additional functions related to inflammatory and immune response was observed. Our data unravel unexpected actions of ERa in breast cancer cells and provide a novel framework to understand success and failure of hormone therapy in breast cancer. Overall design: Examination of unligandend estrogen receptor alpha (aERa) DNA interactions in control and aERa siRNA treated MCF7 cells.
Dissecting the genomic activity of a transcriptional regulator by the integrative analysis of omics data.
No sample metadata fields
View SamplesThe experiment aims to identify transcriptional effects differences between periimplantitis, Parodontitis and healthy gingival tissue
Peri-implantitis versus periodontitis: functional differences indicated by transcriptome profiling.
Specimen part
View SamplesDuring vertebrate limb development, Hoxd genes are regulated following a bimodal strategy involving two topologically associating domains (TADs) located on either side of the gene cluster. These regulatory landscapes alternatively control different subsets of Hoxd targets, first into the arm and, subsequently, into the digits. We studied the transition between these two global regulations, a switch that correlates with the positioning of the wrist, which articulates these two main limb segments. We show that the HOX13 proteins themselves help switch off the telomeric TAD, likely through a global repressive mechanism. At the same time, they directly interact with distal enhancers to sustain the activity of the centromeric TAD, thus explaining both the sequential and exclusive operating processes of these two regulatory domains. We propose a model whereby the activation of Hox13 gene expression in distal limb cells both interrupts the proximal Hox gene regulation and re-enforces the distal regulation. In the absence of HOX13 proteins, a proximal limb structure grows without any sign of wrist articulation, likely related to an ancestral fish-like condition. Overall design: RNA-seq analysis of proximal and distal forelimbs from E12.5 wt or Hoxa13-/-;Hoxd13-/- mutant embryos
A role for HOX13 proteins in the regulatory switch between TADs at the HoxD locus.
Specimen part, Cell line, Subject
View SamplesIn this work we have analyzed the transcriptomic profiles of E13.5 mouse embryonic mammary buds. We show that Hoxd8 and Hoxd9, two gene members of the HoxD cluster, are transcribed during mammary bud development. Yet, unlike in other developmental contexts, their co-expression does not rely upon the same regulatory mechanism. Hoxd8 is regulated by the combined activity of closely located sequences and the most distant telomeric gene desert. On the other hand, Hoxd9 is controlled by an enhancer sequence also located within the telomeric gene desert, but which has no impact on Hoxd8 transcription, thus constituting an exception to the global regulations systematically observed at this locus. The latter DNA region is also involved in Hoxd gene regulation in other contexts and strongly interacts with Hoxd9 in all tissues analyzed so far as well as in other vertebrate species, indicating that its regulatory activity was already operational before the appearance of mammary glands. Within this DNA region and neighboring the CS39 limb enhancer, we further identified a short sequence conserved in therian mammals and capable of enhancer activity in the mammary buds. We propose that Hoxd gene regulation in embryonic mammary buds evolved by hijacking a preexisting regulatory landscape, which was already at work before the emergence of mammals in structures such like the limbs or the intestinal tract. Overall design: RNA-seq analysis of e13.5 mammary buds and adjacent embryonic skin
Control of Hoxd gene transcription in the mammary bud by hijacking a preexisting regulatory landscape.
Specimen part, Cell line, Subject
View SamplesSince the discovery of adult neural stem cells, their exact identity is still under discussion. Moreover, the lack of a reproducible procedure to purify neural stem cells prospectively rather than by growing them in vitro has so far precluded their study at the transcriptome level. Here we demonstrate a novel procedure to prospectively isolate neural stem cells from the adult mouse subependymal zone on the basis of their GFAP- and prominin1-expression by fluorescence-activated cell sorting. All self-renewing, multipotent stem cells are contained in this fraction at 70% purity. The stem cell identity of these double-positive cells is further demonstrated in vivo, by using a novel split-Cre-technology for fate mapping.
In vivo fate mapping and expression analysis reveals molecular hallmarks of prospectively isolated adult neural stem cells.
Specimen part
View SamplesWNT1/beta-catenin signaling plays a crucial role in the generation of mesodiencephalic dopaminergic (mdDA) neurons including the Substantia nigra pars compacta (SNc) subpopulation, whose degeneration is a hallmark of Parkinsons Disease (PD). However, the precise functions of WNT/beta-catenin signaling in this context remain unknown. Using mutant mice, primary ventral midbrain (VM) cells and pluripotent stem cells (mouse embryonic stem cells and induced pluripotent stem cells), we show that Dickkopf 3 (DKK3), a secreted glycoprotein that modulates WNT/beta-catenin signaling, is specifically required for the correct differentiation of a rostrolateral mdDA precursor subset into SNc DA neurons.
Dickkopf 3 Promotes the Differentiation of a Rostrolateral Midbrain Dopaminergic Neuronal Subset In Vivo and from Pluripotent Stem Cells In Vitro in the Mouse.
Specimen part
View SamplesMissense mutations in coding region of PDX1 predispose to type-2 diabetes mellitus as well as cause MODY through largely unexplored mechanisms. Here, we screened a large cohort of subjects with increased risk for diabetes and identified two subjects with impaired glucose tolerance carrying heterozygous missense mutations in the PDX1 coding region leading to single amino acid exchanges (P33T, C18R) in its transactivation domain. We generated iPSCs from patients with heterozygous PDX1P33T/+, PDX1C18R/+ mutations and engineered isogenic cell lines carrying homozygous PDX1P33T/P33T, PDX1C18R/C18R mutations and a heterozygous PDX1 loss-of-function mutation (PDX1+/-). Using an in vitro ß-cell differentiation protocol, we demonstrated that both PDX1P33T/+, PDX1C18R/+ and PDX1P33T/P33T, PDX1C18R/C18R mutations impair ß-cell differentiation and function. Furthermore, PDX1+/- and PDX1P33T/P33T mutations reduced differentiation efficiency of pancreatic progenitors (PPs), due to downregulation of PDX1-bound genes, including transcription factors MNX1 and PDX1 as well as insulin resistance gene CES1. Additionally, both PDX1P33T/+ and PDX1P33T/P33T mutations in PPs reduced the expression of PDX1-bound genes including the long-noncoding RNA, MEG3 and the imprinted gene NEURONATIN, both involved in insulin synthesis and secretion. Our results reveal mechanistic details of how diabetes-associated PDX1 point mutations impair human pancreatic endocrine lineage formation and ß-cell function and contribute to pre-disposition for diabetes. Overall design: We performed RNA-seq of control and isogenic PDX1 mutant cell lines at PP stage
Point mutations in the PDX1 transactivation domain impair human β-cell development and function.
Subject
View SamplesWe report here mRNA-seq data of adult male Drosophila head tissues. We compare two different ages: young and midlife as well as chm/chameau (CG5229) heterozygous mutants. Overall design: Comparison of ageing effect (young vs. midlife) in wild-type and mutant.
Life span extension by targeting a link between metabolism and histone acetylation in Drosophila.
Sex, Subject
View SamplesMicrophthalmos is a rare congenital anomaly characterized by reduced eye size and visual deficits of variable degrees. Sporadic and hereditary microphthalmos has been associated to heterozygous mutations in genes fundamental for eye development. Yet, many cases are idiopathic or await the identification of molecular causes. Here we show that haploinsufficiency of Meis1, a transcription factor with an evolutionary conserved expression in the embryonic trunk, brain and sensory organs, including the eye, causes microphthalmic traits and visual impairment, in adult mice. In the trunk, Meis1 acts as a cofactor for genes of the Hox complex, mostly binding to Hox-Pbx target sequence on the DNA. By combining the analysis of Meis1 loss-of-function and conditional Meis1 functional rescue with ChIPseq and RNAseq approaches, we show that during the development of the optic cup, an Hox-free region, Meis1 binds instead to Hox/Pbx-independent Meis binding site, and coordinates, in a dose-dependent manner, retinal proliferation and differentiation by regulating the expression of components of the Notch signalling pathway. Meis1 also controls the activity of genes responsible for human microphthalmia and eye patterning so that in Meis1-/- embryos, the eye size is reduced and boundaries among the different eye territories are shifted or blurred. We thus propose that Meis1 is at the core of a genetic network implicated in microphthalmia, itself representing an additional candidate for syndromic cases of these ocular malformations. Overall design: Transcriptomics and Meis1 Occupancy analysis on mouse isolated optic cups and ChIP data for histone methylation marks were obtained from about 100 eyes of E10.5 CD1 embryos.
Meis1 coordinates a network of genes implicated in eye development and microphthalmia.
No sample metadata fields
View SamplesSurgical removal of the lens from larval Xenopus laevis results in a rapid transdifferention of central corneal cells to form a new lens. The trigger for this process is understood to be an induction event arising from the unprecedented contact between the cornea and the vitreous humour that occurs following lens removal. The identity of this trigger is unknown. Here, we have used a functional transgenic approach to show that BMP signalling is required for lens regeneration and a microarray approach to identify genes that are upregulated specifically during this process. Analysis of the array data strongly implicates Wnt signalling and Pitx transcription factors in this process. Pluripotency genes, in contrast, are not upregulated, supporting the idea that corneal cells transdifferentiate without returning to a stem cell state. Furthermore, several genes from the array were expressed in the forming lens during embryogenesis. One of these, nipsnap1, is a known direct target of BMP signalling. We suggest that, as with tail regeneration, activation of multiple developmental signalling pathways could drive lens regeneration from the cornea.
Transdifferentiation from cornea to lens in Xenopus laevis depends on BMP signalling and involves upregulation of Wnt signalling.
Specimen part
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