Pseudoautosomal regions (PAR1 and PAR2) in eutherians retain homologous regions between the X and Y chromosomes that play a critical role in the obligatory X-Y crossover during male meiosis. Genes that reside in the PAR1 are exceptional in that they are rich in repetitive sequences and undergo a very high rate of recombination. Remarkably, murine PAR1 homologs have translocated to various autosomes, reflecting the complex recombination history during the evolution of the mammalian X chromosome. We now report that the SNF2-type chromatin remodeling protein ATRX controls the expression of eutherians ancestral PAR1 genes that have translocated to autosomes in the mouse. In addition, we have identified two potentially novel mouse PAR1 orthologs. We propose that the ancestral PAR1 genes share a common epigenetic environment that allows ATRX to control their expression.
The SWI/SNF protein ATRX co-regulates pseudoautosomal genes that have translocated to autosomes in the mouse genome.
Sex
View SamplesMutations in the PTEN, TP53 and RB1 pathways are obligate events in the pathogenesis of human glioblastomas, the highest grade of astrocytoma. To investigate synergy between these tumor suppressors in mice, we induced various combinations of compound deletions conditionally in astrocytes and neural precursors in the mature brain. The resulting highly penetrant astrocytomas showed a spectrum of histopathological variation reminiscent of human tumors, and ranged from grade III to grade IV (glioblastoma). Secondary somatic mutations varied depending on the combination of initiating deletions and were relevant to human disease. Receptor tyrosine kinase amplifications were frequent in tumors initiated by combined conditional deletion of Pten and Tp53, but not when Rb, Pten and Tp53 were simultaneously deleted. Multiple mutations within PI3K and Rb pathways were acquired, however, Mapk activation was not consistently detected in astrocytomas. Gene expression profiling revealed striking similarities to previously described human astrocytoma subclasses. A subset of astrocytomas initiated outside of proliferative niches in the adult brain.
Cooperativity within and among Pten, p53, and Rb pathways induces high-grade astrocytoma in adult brain.
Sex, Specimen part
View SamplesThe two vertebrate Gsk-3 isoforms, Gsk-3a and Gsk-3b, are encoded by distinct genetic loci and exhibit mostly redundant function in murine embryonic stem cells (ESCs). Here we report that deletion of both Gsk-3a and Gsk-3b in mouse ESCs results in significant changes in gene expression. In contrast, deletion of either Gsk-3a or Gsk-3b individually had little effect on gene expression. These data support the notion that Gsk-3 isoforms are functionally redundant in embryonic stem cells. In addition, we did not find the expected upregulation of known Wnt target genes. Our data suggests that Gsk-3-meidated regulation of gene expression in embryonic stem cells is complex, and likely involves affects on numerous signaling pathways.
No associated publication
Specimen part
View SamplesThe two vertebrate Gsk-3 isoforms, Gsk-3a and Gsk-3b, are encoded by distinct genetic loci and exhibit mostly redundant function in murine embryonic stem cells (ESCs). Here we report that deletion of both Gsk-3a and Gsk-3b in mouse ESCs results in misregulated expression of imprinted genes and hypomethylation of corresponding imprinted loci. Treatment of wild-type ESCs with small molecule inhibitors of Gsk-3 phenocopies the DNA hypomethylation of imprinted loci observed in Gsk-3 null ESCs. We provide evidence that DNA hypomethylation in Gsk-3 null ESCs is due to a reduction in the levels of the de novo DNA methyltransferase, Dnmt3a2.
Phosphatidylinositol 3-kinase (PI3K) signaling via glycogen synthase kinase-3 (Gsk-3) regulates DNA methylation of imprinted loci.
Specimen part
View SamplesTo predict Rp58-regulated gene involved in myogenesis, RNA profiling experiments were performed, comparing RNA derived from C2C12 with or without expressing shRNA for Rp58. As a result, 271 genes were upregulated in C2C12 stably expressing shRNA-Rp58 cells compared with control C2C12 cells. As Rp58 is repressor in C2C12, we hypothesized that Rp58 regulates gene cluster which expression is downregulated in accordance with Rp58 expression and myogenesis progression. In this regard, we also characterized dynamic gene expression patterns during myogenesis by microarray at 4 different stage (GM, day 0, 2, 4) of C2C12 myogenesis assays and found that 399 genes expression is characterized as downregulation pattern during myogenesis. Importantly, this down regulation gene set and upregulated genes by shRNA for Rp58 were highly overlapped.
No associated publication
No sample metadata fields
View SamplesAnalysis of mouse chondrocytes lacking the microRNA-140. MicroRNAs are genomically encoded small RNAs to regulate the gene expression. miR-140 shows high expression in cartilage. Results provide insight into the molecular mechanisms underlying miR-140 function in chondrocytes.
MicroRNA-140 plays dual roles in both cartilage development and homeostasis.
Specimen part
View SamplesGenomic technologies have unmasked molecularly distinct subgroups among tumors of the same histological type; but understanding the biologic basis of these subgroups has proved difficult since their defining alterations are often numerous, and the cellular origins of most cancers remain unknown. We sought to decipher complex genomic data sets by matching the genetic alterations contained within these, with candidate cells of origin, to generate accurate disease models. Using an integrated genomic analysis we first identified subgroups of human ependymoma: a form of neural tumor that arises throughout the central nervous system (CNS). Validated alterations included amplifications and homozygous deletions of genes not yet implicated in ependymoma. Matching the transcriptomes of human ependymoma subgroups to those of distinct types of mouse radial glia (RG)neural stem cells (NSCs) that we identified previously to be a candidate cell of origin of ependymoma - allowed us to select RG types most likely to represent cells of origin of disease subgroups. The transcriptome of human cerebral ependymomas that amplify EPHB2 and delete INK4A/ARF matched most closely that of embryonic cerebral Ink4a/Arf-/- RG: remarkably, activation of EphB2 signaling in this RG type, but not others, generated highly penetrant ependymomas that modeled accurately the histology and transcriptome of one human cerebral tumor subgroup (subgroup D). Further comparative genomic analysis revealed selective alterations in the copy number and expression of genes that regulate neural differentiation, particularly synaptogenesis, in both mouse and human subgroup D ependymomas; pinpointing this pathway as a previously unknown target of ependymoma tumorigenesis. Our data demonstrate the power of comparative genomics to sift complex genetic data sets to identify key molecular alterations in cancer subgroups.
Cross-species genomics matches driver mutations and cell compartments to model ependymoma.
Sex, Age, Specimen part, Disease, Disease stage
View SamplesThis SuperSeries is composed of the SubSeries listed below.
A mouse model of the most aggressive subgroup of human medulloblastoma.
Specimen part
View SamplesMouse models of medulloblastoma are compared to human subgroups through microarray expression and other measures
A mouse model of the most aggressive subgroup of human medulloblastoma.
No sample metadata fields
View SamplesWe examined the transformation susceptibility of different cerebellar stem/progenitors by developing several new Group3 medulloblastoma murine models using orthotopic transplantation and in utero electroporation (EP)-based in vivo gene transfer with Cre/LoxP-mediated conditional Myc gene activation and loss of Trp53 function.
No associated publication
No sample metadata fields
View Samples