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The DNA methylomes of hyper-IgM syndrome type 2 B cells provide insights into the roles of activation-induced deaminase prior to the germinal center reaction

ABSTRACT: The DNA methylomes of hyper-IgM syndrome type 2 B cells provide insights into the roles of activation-induced deaminase prior to the germinal center reaction

PROVIDER: PRJNA556010 | ENA |

REPOSITORIES: ENA

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			Action	DRS
	SRR9730300_1.fastq.gz	Fastqsanger.gz
	SRR9730300_2.fastq.gz	Fastqsanger.gz
	SRR9730310_1.fastq.gz	Fastqsanger.gz
	SRR9730310_2.fastq.gz	Fastqsanger.gz
	SRR9730320_1.fastq.gz	Fastqsanger.gz

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Similar Datasets

The DNA methylomes of hyper-IgM syndrome type 2 B cells provide insights into the roles of activation-induced deaminase prior to the germinal center reaction

Project description:Inactivating mutations in activation induced deaminase (AID) lead to hyper-IgM syndrome type 2 (HIGM2), a rare primary antibody deficiency. AID-mediated cytosine deamination has been proposed as mediating active demethylation, although there is evidence both to support and cast doubt on such a role. We here made use of HIGM2 B cells to investigate direct AID involvement in active DNA demethylation. HIGM2 naïve and memory B cells both display widespread DNA methylation defects. For genes that undergo demethylation in the transition from naïve to memory B cells but not in HIGM2 individuals, we did not observe AID involvement but a participation of TET enzymes. DNA methylation alterations in HIGM2 naïve B cells are related to premature overstimulation of the B-cell receptor prior to the germinal center reaction. Our data supports a role for AID in B cell central tolerance in preventing the expansion of autoreactive cell clones, affecting the correct establishment of DNA methylation patterns without involvement of its cytosine deaminase activity.

2020-12-31 | GSE134664 | GEO

Activation-induced deaminase is critical for the establishment of DNA methylation patterns prior to the germinal center reaction

Project description:Activation-induced deaminase (AID) initiates antibody diversification in germinal center B cells by deaminating cytosines, leading to somatic hypermutation and class-switch recombination. Loss-of-function mutations in AID lead to hyper-IgM syndrome type 2 (HIGM2), a rare human primary antibody deficiency. AID-mediated deamination has been proposed as leading to active demethylation of 5-methycytosines in the DNA, although evidence both supports and casts doubt on such a role. In this study, using whole-genome bisulfite sequencing of HIGM2 B cells, we investigated direct AID involvement in active DNA demethylation. HIGM2 naïve and memory B cells both display widespread DNA methylation alterations, of which approximately 25% are attributable to active DNA demethylation. For genes that undergo active demethylation that is impaired in HIGM2 individuals, our analysis discards AID involvement. We demonstrate that the widespread alterations in the DNA methylation and expression profiles of HIGM2 naïve B cells result from premature overstimulation of the B-cell receptor prior to the germinal center reaction. Our data support a role for AID in B cell central tolerance in preventing the expansion of autoreactive cell clones, affecting the correct establishment of DNA methylation patterns.

2021-04-13 | GSE172011 | GEO

The DNA methylome and transcriptome of hyper-IgM syndrome type 2 B cells

Project description:The DNA methylome and transcriptome of hyper-IgM syndrome type 2 B cells

| PRJNA721695 | ENA

Activation-induced deaminase is critical for the establishment of DNA methylation patterns prior to the germinal center reaction

Project description:Activation-induced deaminase is critical for the establishment of DNA methylation patterns prior to the germinal center reaction

| PRJNA721698 | ENA

Activation-induced cytidine deaminase expression and activity in the absence of germinal centers: insights into hyper-IgM syndrome.

Project description:Somatic hypermutation normally occurs as a consequence of the expression of activation-induced cytidine deaminase (AID) by Ag-activated, mature B cells during T cell-dependent germinal center responses. Nonetheless, despite their inability to express CD154 and initiate GC responses, patients with type 1 hyper-IgM syndrome (HIGM1) support populations of IgM(+)IgD(+)CD27(+) B cells that express mutated Ig genes. The origin of these mutated B cells is unknown; the IgM(+)IgD(+)CD27(+) cells do not express AID and appear to acquire mutations independent of stringent selection by Ag. Here, we demonstrate that immature/transitional 1 B cells from the bone marrow of CD154-deficient mice express AID and acquire Ig mutations that lack the hallmarks of antigenic selection via BCR signaling. Comparable levels of AID expression was found in developmentally immature B cells recovered from murine fetal liver and from human immature/transitional 1 B cells recovered from umbilical cord blood. AID expression in human fetal liver was also robust, approaching that of human tonsil tissue and the human germinal center B cell line, Ramos. These observations led us to conclude that AID expression in developing human B cells is the origin of the mutated IgM(+)IgD(+)CD27(+) B cells present in HIGM1 patients, and we propose that both mice and humans share a latent, AID-dependent pathway for the preimmune diversification of B lymphocytes that is more prominent in chicken, sheep, and rabbits.

| S-EPMC2779701 | biostudies-literature

A study of pharmacokinetic analysis of capecitabine and cytidine deaminase activity

Project description:Interventions: Blood samples(10 points) are collected after the first administration of capecitabine for pharmacokinetic analysis and cytidine deaminase activity measurement. Primary outcome(s): To evaluate the correlation AUC of 5-DFUR/AUC of 5-DFCR ratio and cytidine deaminase activity. Study Design: Single arm Non-randomized

| 2634538 | ecrin-mdr-crc

A Hyper-IgM Syndrome Mutation in Activation-Induced Cytidine Deaminase Disrupts G-Quadruplex Binding and Genome-wide Chromatin Localization.

Project description:Precise targeting of activation-induced cytidine deaminase (AID) to immunoglobulin (Ig) loci promotes antibody class switch recombination (CSR) and somatic hypermutation (SHM), whereas AID targeting of non-Ig loci can generate oncogenic DNA lesions. Here, we examined the contribution of G-quadruplex (G4) nucleic acid structures to AID targeting in vivo. Mice bearing a mutation in Aicda (AIDG133V) that disrupts AID-G4 binding modeled the pathology of hyper-IgM syndrome patients with an orthologous mutation, lacked CSR and SHM, and had broad defects in genome-wide AIDG133V chromatin localization. Genome-wide analyses also revealed that wild-type AID localized to MHCII genes, and AID expression correlated with decreased MHCII expression in germinal center B cells and diffuse large B cell lymphoma. Our findings indicate a crucial role for G4 binding in AID targeting and suggest that AID activity may extend beyond Ig loci to regulate the expression of genes relevant to the physiology and pathology of activated B cells.

| S-EPMC8356774 | biostudies-literature

A structural basis for the biochemical behavior of activation-induced deoxycytidine deaminase class-switch recombination-defective hyper-IgM-2 mutants.

Project description:Hyper-IgM syndrome type 2 stems from mutations in activation-induced deoxycytidine deaminase (AID) that abolish immunoglobulin class-switch recombination, causing an accumulation of IgM and absence of IgG, IgA, and IgE isotypes. Although hyper-IgM syndrome type 2 is rare, the 23 missense mutations identified in humans span almost the entire gene for AID resulting in a recessive phenotype. Using high resolution x-ray structures for Apo3G-CD2 as a surrogate for AID, we identify three classes of missense mutants as follows: catalysis (class I), substrate interaction (class II), and structural integrity (class III). Each mutant was expressed and purified from insect cells and compared biochemically to wild type (WT) AID. Four point mutants retained catalytic activity at 1/3rd to 1/200th the level of WT AID. These "active" point mutants mimic the behavior of WT AID for motif recognition specificity, deamination spectra, and high deamination processivity. We constructed a series of C-terminal deletion mutants (class IV) that retain catalytic activity and processivity for deletions ?18 amino acids, with ?C(10) and ?C(15) having 2-3-fold higher specific activities than WT AID. Deleting 19 C-terminal amino acids inactivates AID. WT AID and active and inactive point mutants bind cooperatively to single-stranded DNA (Hill coefficients ?1.7-3.2) with microscopic dissociation constant values (K(A)) ranging between 10 and 250 nm. Active C-terminal deletion mutants bind single-stranded DNA noncooperatively with K(A) values similar to wild type AID. A structural analysis is presented that shows how localized defects in different regions of AID can contribute to loss of catalytic function.

| S-EPMC3431652 | biostudies-literature

Grass carp serum IgM LC-ESI-MS/MS and MALDI-MS

Project description:Glycosylation represents a major post-translational modification of proteins that can influence their structure and function.Telesot immunoglobulin M (IgM) is an especially important product of the immune system because it is the main Abs in seum and plays a critical role against defense infection. However, little is known regarding site-specific N-glycan characteristics in teleost IgM , LC-ESI-MS/MS was used to analysis deglycopeptides and glycopeptides of grass carp serum IgM, and MALDI-MS was used to analysis released carbohydrates by PNGaseF diestion of grass carp serum IgM.

2018-11-29 | PXD010308 | Pride

Non-coding RNA analysis in IgM monoclonal gammopathies: an underrecognized role of microRNA and long non-coding RNA differentiating Waldenström macroglobulinemia from IgM-MGUS

Project description:Waldenström macroglobulinemia (WM), is a rare non-Hodgkin lymphoma preceded by a clinically asymptomatic benign monoclonal gammopathy of undetermined significance (IgM-MGUS). The factors underlying the malignant progression between these two IgM-monoclonal gammopathies remain poorly understood. The non-coding genome is increasingly recognized as an important driver of disease pathogenesis, and there remains a lack of exploration of the influence of non-coding RNAs within the IgM-monoclonal gammopathy disease spectrum. The present study explores the role of microRNA (miRNA) and long non-coded RNA (lncRNA) in IgM-gammopathies and specifically elucidates potentially regulated protein-coding genes and pathways. A comprehensive analysis of miRNA, lncRNA and protein-coding coding genes was conducted on 28 subjects, 17 patients with WM, 6 patients with IgM-MGUS, and 5 normal controls. Differential expression analysis revealed a number of dysregulated miRNA and lncRNA between IgM-gammopathies compared to normal controls and specifically between IgM-MGUS and WM. Pathway analysis was conducted utilizing differentially expressed mRNA with correlated biological expression of targeting miRNA. Here, a number of pathways were implicated influencing a gamut of cellular functions, including cell signaling, metabolism, replication, and immune regulation in both WM compared to IgM-MGUS and IgM-gammopathies compared to controls. This report is additionally one of the first published analyses of lncRNAs in WM, where we demonstrate a number of lncRNA associated with transcription and apoptosis regulation genes in WM compared to IgM-MGUS. This study highlights the role of non-coding RNA in IgM-gammopathies and the potential to recognize novel targets which may halt or slow the malignant progression between these two diseases.

2023-12-08 | GSE232995 | GEO

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