Ontology highlight
ABSTRACT:
PROVIDER: PRJNA830503 | ENA |
REPOSITORIES: ENA
Similar Datasets
Project description:SETD2 haploinsufficiency enhances germinal center-associated AICDA somatic hypermutation to drive B-cell lymphomagenesis
| PRJNA784920 | ENA
Project description:SETD2 is the sole chromatin modifier responsible for H3K36me3, a histone mark linked to splicing, transcription initiation and DNA damage response. Homozygous disruption of SETD2 yields a tumor suppressor effect in various cancers. However, SETD2 mutation is virtually always heterozygous in diffuse large B-cell lymphomas (DLBCL). Here we show that heterozygous SETD2 deficiency results in germinal center (GC) hyperplasia and accelerated lymphomagenesis. SETD2 haploinsufficient GC B-cells exhibit increased competitive fitness and reduced DNA damage checkpoint activity, resulting in decreased apoptosis. SETD2 haploinsufficient GCB and lymphoma cells featured increased off- and on-target AICDA induced somatic hypermutation (SHM), complex structural variants such as rygma, and increased translocations including those activating MYC. DNA damage was selectively increased on the non-template strand and H3K36me3 loss was associated with greater RNA Pol II processivity and mutational burden, suggesting that SETD2-mediated H3K36me3 is required for proper sensing of cytosine deamination during transcription. Hence, SETD2 haploinsufficiency delineates a novel GC B-cell context specific oncogenic pathway involving defective epigenetic surveillance of AICDA mediated somatic hypermutation induced off target effects on transcribed genes.
2022-04-06 | GSE189867 | GEO
Project description:Changes in DNA methylation are required for the formation of germinal centers (GC), but the mechanisms of such changes are poorly understood. Activation-induced cytidine deaminase (AID) has been recently implicated recently in DNA demethylation through its deaminase activity coupled with DNA repair. We investigated the epigenetic function of AID in vivo in germinal center B cells (GCB) isolated from wild type (WT) and AID-deficient (Aicda-/-) mice. We determined that the transit of B cells through the GC is associated with marked locus-specific loss of methylation and increased methylation diversity, both of which are lost in Aicda-/- animals. Differentially methylated cytosines (DMCs) between GCB and naïve B cells (NB) are enriched in genes that are targeted for somatic hypermutation (SHM) by AID and these genes form networks required for B cell development and proliferation. Finally, we observed significant conservation of AID-dependent epigenetic reprogramming between mouse and human B cells. ERRBS and RNA-seq of wild type and Aicda knockout murine naive and germinal center B cells. ERRBS of human naive and germinal center B cells
2015-09-15 | E-GEOD-71702 | biostudies-arrayexpress
Project description:Productive B cell responses are critical to protect a host from infection. The spleen and lymph nodes are populated by resting follicular B cells, which can enter germinal centers upon antigen encounter. Once in the germinal center, B cells migrate between the dark and light zones, where they undergo somatic hypermutation and selection, respectively. While germinal center B cells have been studied, an intense molecular understanding of these cells/subsets (and the differences between them) is lacking.
2020-04-06 | PXD015524 | Pride
Project description:AICDA-induced epigenetic plasticity accelerates germinal center-derived lymphomagenesis
| PRJNA375214 | ENA
Project description:Changes in DNA methylation are required for the formation of germinal centers (GC), but the mechanisms of such changes are poorly understood. Activation-induced cytidine deaminase (AID) has been recently implicated recently in DNA demethylation through its deaminase activity coupled with DNA repair. We investigated the epigenetic function of AID in vivo in germinal center B cells (GCB) isolated from wild type (WT) and AID-deficient (Aicda-/-) mice. We determined that the transit of B cells through the GC is associated with marked locus-specific loss of methylation and increased methylation diversity, both of which are lost in Aicda-/- animals. Differentially methylated cytosines (DMCs) between GCB and naïve B cells (NB) are enriched in genes that are targeted for somatic hypermutation (SHM) by AID and these genes form networks required for B cell development and proliferation. Finally, we observed significant conservation of AID-dependent epigenetic reprogramming between mouse and human B cells.
2015-09-15 | GSE71702 | GEO
Project description:The MEF2B transcription factor is frequently mutated in germinal center (GC)-derived B-cell lymphomas. Its N-terminal mutations drive lymphomagenesis by escaping interaction with transcriptional repressors, while the function of C-terminal mutations remains to be elucidated. Here, we show that MEF2B C-tail is physiologically phosphorylated at specific residues and phosphorylation at S324 is impaired by lymphoma-associated mutations. Lack of phosphorylation at S324 enhances the interaction of MEF2B with the SWI/SNF chromatin remodeling complex, leading to higher transcriptional activity. In addition, these mutants show an increased protein stability due to impaired interaction with the CUL3/KLHL12 ubiquitin complex. Mice expressing a phosphorylation-deficient lymphoma-associated MEF2B mutant display GC enlargement and develop GC-derived lymphomas, when crossed with Bcl2 transgenic mice. These results unveil converging mechanisms of action for a diverse spectrum of MEF2B mutations, all leading to its dysregulation and GC B-cell lymphomagenesis. These assorted mechanisms provide additional opportunities for the development of targeted therapeutic approaches.
2024-08-26 | PXD043998 | Pride
Project description:The goals of this study are to compare gene expression profiles of Setd2 WT and KO germinal center B cells and reveal the underlying mechanisms by which Setd2 regulates germinal center B cell responses. Further our study aims to compare gene expression profiles of Phf19 WT and KO germinal center B cells reveal the underlying mechanisms by which Phf19 regulates germinal center B cells responses. Finally, we combine the two profiles and investigate the relation shape betweeen Setd2 dependent regulation and Phf19 dependent regulation.
2024-09-14 | GSE184075 | GEO
Project description:Somatic hypermutation (SHM) and class switch recombination (CSR) increase the affinity and diversify the effector functions of antibodies during immune responses. Although SHM and CSR are fundamentally different, their independent roles in regulating B cell fate have been difficult to uncouple because a single enzyme, activation-induced cytidine deaminase (encoded by Aicda), initiates both reactions. Here, we used a combination of Aicda and antibody mutant alleles that separate the effects of CSR and SHM on polyclonal immune responses. We found that class-switching to IgG1 biased the fate choice made by B cells, favoring the plasma cell over memory cell fate without significantly affecting clonal expansion in the germinal center (GC). In contrast, SHM reduced the longevity of memory B cells by creating polyreactive specificities that were selected against over time. Our data define the independent contributions of SHM and CSR to the generation and persistence of memory in the antibody system.
2016-10-19 | GSE76865 | GEO
Project description:Somatic hypermutation (SHM) and class switch recombination (CSR) increase the affinity and diversify the effector functions of antibodies during immune responses. Although SHM and CSR are fundamentally different, their independent roles in regulating B cell fate have been difficult to uncouple because a single enzyme, activation-induced cytidine deaminase (encoded by Aicda), initiates both reactions. Here, we used a combination of Aicda and antibody mutant alleles that separate the effects of CSR and SHM on polyclonal immune responses. We found that class-switching to IgG1 biased the fate choice made by B cells, favoring the plasma cell over memory cell fate without significantly affecting clonal expansion in the germinal center (GC). In contrast, SHM reduced the longevity of memory B cells by creating polyreactive specificities that were selected against over time. Our data define the independent contributions of SHM and CSR to the generation and persistence of memory in the antibody system.
2016-10-19 | GSE76864 | GEO