This SuperSeries is composed of the SubSeries listed below.
Molecular classification of mature aggressive B-cell lymphoma using digital multiplexed gene expression on formalin-fixed paraffin-embedded biopsy specimens.
Sex, Age, Specimen part, Disease
View SamplesThe most frequent mature aggressive B-cell lymphomas are diffuse large B-cell lymphoma (DLBCL) and Burkitt lymphoma (BL). Patients suffering from molecularly defined BL (mBL) but treated with a regimen developed for DLBCL show an unfavorable outcome compared to mBL treated with chemotherapy regimens for BL. Distinguishing BL from DLBCL by conventional histopathology is challenging in lymphomas that have features common to both diseases (aggressive B-cell lymphoma unclassifiable with features of DLBCL and BL [intermediates]). Moreover, DLBCL are a heterogeneous group of lymphomas comprising distinct molecular subtypes: the activated B-cell (ABC)-like, the germinal center B-cell-like (GCB) and the unclassifyable subtype as defined by gene expression profiling (GEP). Attempts to replace GEP with techniques applicable to formalin-fixed paraffin-embedded (FFPE) tissue led to algorithms for immunohistochemical stainings (IHS). Disappointingly, the algorithms yielded conflicting results with respect to their prognostic potential, raising concerns about their validity. Furthermore, IHS algorithms did not provide a fully resolved classification: They did not identify mBL; nor did they separate ABC from unclassified DLBCL.
Molecular classification of mature aggressive B-cell lymphoma using digital multiplexed gene expression on formalin-fixed paraffin-embedded biopsy specimens.
Sex, Age, Specimen part
View SamplesThe replication of a genomic region during S-phase can be highly dynamic between cell types that differ in transcriptome and epigenome. Replication timing has been positively correlated with several histone modifications that occur at active genes, while repressive histone modifications mark late replicating regions. This raises the question if chromatin modulates the initiating events of replication. To gain insights into this question we have studied the function of heterochromatin protein 1 (HP1), a reader of to the repressive histone lysine 9 methylation of H3, in genome-wide organization of replication. Cells with reduced levels of HP1 show an advanced replication timing of centromeric repeats in agreement with the model that repressive chromatin mediates the very late replication of large clusters of constitutive heterochromatin. Surprisingly however regions with high levels of interspersed repeats on the chromosomal arms in particular on chromosome 4 and in pericentromeric regions of chromosome 2 behave differently. Here loss of HP1 results in delayed replication timing. The fact that these regions are bound by HP1 suggests a direct effect. Thus while HP1 mediates very late replication of centromeric DNA it is also required for early replication of autosomal regions with high levels of repeats. This observation of opposing functions of HP1 suggests a model where repeat inactivation on autosomes is required for proper activation of origins of replication that fire early, while HP1 mediated repression at constitutive heterochromatin is required to ensure replication of centromeric repeats at the end of S phase.
Heterochromatin protein 1 (HP1) modulates replication timing of the Drosophila genome.
Sex, Specimen part
View SamplesDuplication of eukaryotic genomes during S phase is coordinated in space and time. In order to identify zones of initiation and cell-type as well as gender-specific plasticity of DNA replication, we profiled replication timing, histone acetylation and transcription throughout the Drosophila genome. We observed two waves of replication initiation with many distinct zones firing in early and multiple, less defined peaks at the end of S phase, suggesting that initiation becomes more promiscuous at the end of S phase. A comparison of different cell types revealed widespread plasticity of replication timing on autosomes. Most occur in large regions but only half coincide with local differences in transcription. In contrast to confined autosomal differences, a global shift in replication timing occurs throughout the single male X chromosome. Unlike in females, the dosage compensated X chromosome replicates almost exclusively early. This difference occurs at sites which are not transcriptionally hyperactivated, but show increased acetylation of lysine 16 of histone H4. This suggests a transcription-independent, yet chromosome-wide process related to chromatin. Importantly, H4K16ac is also enriched at initiation zones as well as early replicating regions on autosomes during S phase. Together, our data reveal novel organizational principles of DNA replication of the Drosophila genome and imply chromatin structure as a determinant of replication timing locally and chromosome-wide.
Chromatin state marks cell-type- and gender-specific replication of the Drosophila genome.
Sex
View SamplesChronic infection with the bacterial pathogen Helicobacter pylori is a risk factor for the development of gastric cancer, yet remains asymptomatic in a majority of individuals. We report here that the C57Bl6 mouse model of experimental infection with the closely related H. felis recapitulates this wide range in host susceptibility. A majority of infected mice develop premalignant lesions such as gastric atrophy, compensatory epithelial hyperplasia and intestinal metaplasia, whereas a minority is completely protected from preneoplasia. Protection is associated with the failure to mount an IFN-gamma response to the infection and an associated high Helicobacter burden. We demonstrate that IFN-gamma is essential for clearance of Helicobacter, but also mediates the formation of preneoplastic lesions. We further provide evidence that IFN-gamma triggers a specific transcriptional program in murine gastric epithelial cells in vitro and in vivo, and induces their preferential transformation to the hyperplastic phenotype. In summary, our data suggest a dual role for IFN-gamma in Helicobacter pathogenesis that could provide an explanation for the differential susceptibility to H. pylori-induced gastric pathology in the human population.
The CD4+ T cell-mediated IFN-gamma response to Helicobacter infection is essential for clearance and determines gastric cancer risk.
Treatment
View SamplesPreviously published data suggested some redundant functions between HDAC1 and HDAC2 in mouse. To test this hypothesis, we used microarrays to have a genome wide analysis at the transcription level of primary MEFs lacking HDAC1, HDAC2.
Histone deacetylases 1 and 2 act in concert to promote the G1-to-S progression.
Sex
View SamplesOBF1, also known as Bob.1 or OCA-B, is a B lymphocyte-specific transcription factor which coactivates Oct1 and Oct2 on B cell specific promoters. So far, the function of OBF1 has been mainly identified in late stage B cell populations. The central defect of OBF1 deficient mice is a severely reduced immune response to T cell-dependent antigens and a lack of germinal center formation in the spleen. Relatively little is known about a potential function of OBF1 in developing B cells. Here we have generated transgenic mice overexpressing OBF1 in B cells under the control of the immunoglobulin heavy chain promoter and enhancer. Surprisingly, these mice have greatly reduced numbers of follicular B cells in the periphery and have a compromised immune response. Furthermore, B cell differentiation is impaired at an early stage in the bone marrow. A first block is observed during B cell commitment and a second differentiation block is seen at the large preB2 cell stage. The cells that succeed to escape the block and to differentiate into mature B cells have post-translationally downregulated the expression of transgene, indicating that expression of OBF1 beyond the normal level early in B cell development is deleterious. Indeed ID3, which is a negative regulator of B cell differentiation, is upregulated in the EPLM and preB cells of the transgenic mice. Furthermore ID3 promoter contains an octamer site suggesting that it is a potential OBF-1 direct target gene. These results provide evidence that OBF1 expression has to be tightly regulated in early B cells to allow efficient B lymphocyte differentiation.
Enforced expression of the transcriptional coactivator OBF1 impairs B cell differentiation at the earliest stage of development.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Transcriptional code and disease map for adult retinal cell types.
Specimen part
View SamplesBrain circuits are assembled from a large variety of morphologically and functionally diverse cell types. It is not known how the intermingled cell types of individual brain regions differ in their expressed genomes. Here we describe an atlas of cell type transcriptomes of the adult retina. We found that each adult cell type expresses a specific set of genes, including a unique set of transcription factors, forming a barcode for cell identity. Cell type transcriptomes carry enough information to categorize cells into corresponding morphological classes and types. Surprisingly, several barcode genes are eye disease-associated genes that we demonstrate to be specifically expressed not only in photoreceptors but also in particular retinal circuit elements such as inhibitory neurons as well as in retinal microglia. Our data suggest that distinct cell types of individual brain regions are characterized by marked differences in their expressed genomes.
Transcriptional code and disease map for adult retinal cell types.
Specimen part
View SamplesAnalysis of protein tyrosine phosphatase 1B (PTP1B) deficient mammary glands from nulliparous mice at estrous and pregnancy day 3, 7, 10 and 15. We used a genetically ablated PTP1B mouse model to gain a deeper knowledge of the role PTP1B plays in mammary gland development and to define the mechanism regulated by this phosphatase.
Protein tyrosine phosphatase 1B restrains mammary alveologenesis and secretory differentiation.
Specimen part
View Samples