Epigenetic modifications must underlie lineage-specific differentiation since terminally differentiated cells express tissue-specific genes, but their DNA sequence is unchanged. Hematopoiesis provides a well-defined model of progressive differentiation in which to study the role of epigenetic modifications in cell fate decisions. Multi-potent progenitors (MPPs) can differentiate into all blood cell lineages, while downstream progenitors commit to either myeloerythroid or lymphoid lineages. While DNA methylation is critical for myeloid versus lymphoid differentiation, as demonstrated by the myeloerythroid bias in Dnmt1 hypomorphs {Broske, 2009 #6}, a comprehensive DNA methylation map of hematopoietic progenitors, or of any cell lineage, does not exist. Here we have generated a mouse DNA methylation map, examining 4.6 million CpG sites throughout the genome including all CpG islands and shores, examining MPPs, all lymphoid progenitors (ALPs), common myeloid progenitors (CMPs), granulocyte/macrophage progenitors (GMPs), and thymocyte progenitors (DN1, DN2, DN3). Interestingly, differentiation towards the myeloid lineage corresponds with a net decrease in DNA methylation, while lymphoid commitment involves a net increase in DNA methylation, but both show substantial dynamic changes consistent with epigenetic plasticity during development. By comparing lineage-specific DNA methylation to gene expression array data, we find many examples of genes and pathways not previously known to be involved in lymphoid/myeloid differentiation, such as Gcnt2, Arl4c, Gadd45, and Jdp2. Several transcription factors, including Meis1 and Prdm16 were methylated and silenced during differentiation, suggesting a role in maintaining an undifferentiated state. Additionally, epigenetic modification of modifiers of the epigenome appears to be important in hematopoietic differentiation. Our results directly demonstrate that modulation of DNA methylation occurs during lineage-specific differentiation, often correlating with gene expression changes, and define a comprehensive map of the methylation and transcriptional changes that accompany myeloid versus lymphoid fate decisions.
Comprehensive methylome map of lineage commitment from haematopoietic progenitors.
Sex, Age
View SamplesMost tumors are epithelial-derived, and although disruption of polarity and aberrant cellular junction formation is a poor prognosticator in human cancer, the role of polarity determinants in oncogenesis is poorly understood. Using in vivo selection, we identified a mammalian orthologue of the Drosophila polarity regulator crumbs as a gene whose loss of expression promotes tumor progression. Immortal baby mouse kidney epithelial (iBMK) cells selected in vivo to acquire tumorigenicity displayed dramatic repression of crumbs3 (crb3) expression associated with disruption of tight junction formation, apicobasal polarity, and contact-inhibited growth. Restoration of crb3 expression restored junctions, polarity and contact inhibition, while suppressing migration and metastasis. These findings suggest a role for mammalian polarity determinants in suppressing tumorigenesis that may be analogous to the well-studied polarity tumor suppressor mechanisms in Drosophila.
Role of the polarity determinant crumbs in suppressing mammalian epithelial tumor progression.
No sample metadata fields
View SamplesBrain-derived serotonin favors appetite in mice following its binding to the Htr1a and Htr2b receptors in arcuate neurons of the hypothalamus. In this study, we identified that CREB is the transcriptional effector of brain-derived serotonin control of appetite in arcuate nuclei.
Leptin-dependent serotonin control of appetite: temporal specificity, transcriptional regulation, and therapeutic implications.
Age, Specimen part
View SamplesWe report high-throughput profiling of gene expression from whole zebrafish ventricles. We profile mRNA in uninjured ventricles and those undergoing regeneration 14 days after genetic ablation. This study provides a framework for understanding transcriptional changes during adult models of regeneration. Overall design: Examination of gene expression in cardiomyocytes under different states of proliferation.
Resolving Heart Regeneration by Replacement Histone Profiling.
No sample metadata fields
View SamplesExtensive molecular profiling of leukemias and preleukemic diseases has revealed that distinct clinical entities, like acute myeloid (AML) and T-lymphoblastic leukemia, share the same pathogenetic mutations. It is not well understood how the cell of origin, accompanying mutations, extracellular signals or structural differences in a mutated gene determine the phenotypic identity of the malignant disease. We studied the relationship of different protein domains of the MN1 oncogene and their effect on the leukemic phenotype, building on the ability of MN1 to induce leukemia without accompanying mutations. We found that the most C-terminal domain of MN1 was required to block myeloid differentiation at an early stage, and deletion of an extended C-terminal domain resulted in loss of myeloid identity and cell differentiation along the T-cell lineage in vivo. Megakaryocytic/erythroid lineage differentiation was blocked by the most N-terminal domain. In addition, the N-terminus was required for proliferation and leukemogenesis in vitro and in vivo through upregulation of HoxA9, HoxA10 and Meis2. Our results provide evidence that a single oncogene can modulate cellular identity of leukemic cells based on its active domains. It is therefore likely that different mutations in the same oncogene may impact cell fate decisions and phenotypic appearance of malignant diseases.
Cell fate decisions in malignant hematopoiesis: leukemia phenotype is determined by distinct functional domains of the MN1 oncogene.
Specimen part
View SamplesNumerous studies have established a critical role for BMP signaling in skeletal development. In the developing axial skeleton, sequential SHH and BMP signals are required for specification of a chondrogenic fate in somitic tissue. A similar paradigm is thought to operate in the limb, but the signals involved are unclear. To investigate the nature of these signals we examined BMP action in mesenchymal populations derived from the early murine limb bud (~ E10.5). These populations exhibited a graded response to BMPs, in which early limb mesenchymal (EL) cells (from the distal hind limb) displayed an anti-chondrogenic response, whereas BMPs promoted chondrogenesis in older cell populations. To better understand the molecular basis of disparate BMP action in these various populations, gene expression profiling with Affymetrix microarrays was employed to identify BMP-regulated genes. These analyses showed that BMPs induced a distinct gene expression pattern in the EL cultures versus later mesenchymal limb populations (IM and LT).
Regulation of BMP-dependent chondrogenesis in early limb mesenchyme by TGFbeta signals.
Specimen part
View SamplesWnt9b is expressed in the ureteric bud of the kidney at all stages of development. In Wnt9b mutants, the ureteric bud forms but the metanephric mesenchyme is never induced to undergo differentiation.
Myc cooperates with β-catenin to drive gene expression in nephron progenitor cells.
Specimen part
View SamplesHelicobacter pylori clinical isolates can establish themselves in gastric epithelial stem cells and this interaction may have implications for gastric tumorigenesis. Mouse gastric epithelial progenitor cells (mGEPs) and non-progenitor gastric epithelial cells (npGECs) were infected for 24hrs with Helicobacter pylori clinical isolates Kx1 and Kx2. Kx1 was isolated from a patient with chronic atrophic gastritis (ChAG) and Kx2 from the same patient 4 years later, when he progressed to gastric adenocarcinoma.
Helicobacter pylori evolution during progression from chronic atrophic gastritis to gastric cancer and its impact on gastric stem cells.
No sample metadata fields
View SamplesNormal adult liver is uniquely capable of renewal
Restoration of liver mass after injury requires proliferative and not embryonic transcriptional patterns.
Age
View SamplesWe characterized gene expression changes in the developing mouse liver at gestational days (GD) 11.5, 12.5, 13.5, 14.5, 16.5, and 19.5 and in the neonate (postnatal day (PND) 7 and 30) using full-genome microarrays and compared these changes to that in the adult liver. The fetal liver, and to a lesser extent the neonatal liver, exhibited dramatic differences in gene expression compared to adults. Canonical pathway analysis of the fetal liver signature demonstrated increases in functions important in cell replication and DNA fidelity whereas most metabolic pathways of intermediary metabolism were suppressed. Comparison of the dataset to a number of previously published datasets revealed 1) a striking similarity between the fetal liver and that of the pancreas in both mice and humans, 2) a nucleated erythrocyte signature in the fetus and 3) suppression of most xenobiotic metabolism genes throughout development, except a number of transporters associated with expression in hematopoietic cells.
Transcriptional ontogeny of the developing liver.
Specimen part
View Samples