Programmed mutagenesis of the immunoglobulin locus of B-lymphocytes during class switch recombination and somatic hypermutation requires RNA polymerase II (RNA polII) transcription complex dependent targeting of the DNA mutator, Activation Induced cytidine Deaminase (AID). AID deaminates cytidine residues on substrate sequences in the immunoglobulin (Ig) locus via a transcription-dependent mechanism and this activity is stimulated by the RNA polII stalling co-factor Spt5 and the eleven-subunit cellular non-coding RNA 3’-5’ exonucleolytic processing complex, RNA exosome. The mechanism by which the RNA exosome recognizes immunoglobulin locus RNA substrates to stimulate AID DNA deamination activity on its in vivo substrate sequences is an important question. Here we report that E3-ubiquitin ligase Nedd4 destabilizes AID-associated RNA polII by a ubiquitination event leading to generation of 3’-end free RNA exosome RNA substrates at the Ig locus and other AID target sequences genome-wide. Using highthrough-out RNA sequencing technology, we find that lack of Nedd4 activity in B cells leads to accumulation of RNA exosome substrates at AID target genes. Moreover, we find that Nedd4-deficient B cells are inefficient in undergoing class switch recombination. Taken together, our study links non-coding RNA processing following RNA polymerase II pausing with regulation of the mutator AID protein. Our study also identifies Nedd4 as a regulator of non-coding RNA that are generated by stalled RNA polII genome-wide. Overall design: Splenic B cells from Nedd4+/+ and Nedd4-/- B cells fetal liver chimeric mice were were stimulated in culture for IgG1 CSR. Total RNA was isolated and evaluated with whole genome RNA-seq
E3-ubiquitin ligase Nedd4 determines the fate of AID-associated RNA polymerase II in B cells.
Specimen part, Subject
View SamplesSRSF2 is an RNA binding protein that plays important roles in splicing of mRNA precursors. Mutations in SRSF2 are frequently found in patients with myelodysplastic syndromes and certain leukemias, but how they affect SRSF2 function has only begun to be examined. Here we used CRISPR/Cas9 to introduce the P95H mutation to SRSF2 in K562 leukemia cells, generating an isogenic model so that splicing alterations can be attributed solely to mutant SRSF2. We found that SRSF2 (P95H) misregulates 548 splicing events (<1% of total). Of these, 374 involve the inclusion of cassette exons, and the inclusion was either increased (206) or decreased (168). We detected a specific motif (UCCA/UG) enriched in the more included exons and a distinct motif (UGGA/UG) in the more excluded exons. RNA gel shift assays showed that a mutant SRSF2 derivative bound more tightly than its wild-type counterpart to RNA sites containing UCCAG, but less tightly to UGGAG sites. The pattern of exon inclusion or exclusion thus correlated in most cases with stronger or weaker RNA binding, respectively. We further show that the P95H mutation does not affect other functions of SRSF2, i.e., protein-protein interactions with key splicing factors. Our results thus demonstrate that the P95H mutation positively or negatively alters the binding affinity of SRSF2 for cognate RNA sites in target transcripts, leading to misregulation of exon inclusion. Our findings not only shed light on the mechanism of the disease-associated SRSF2 mutation in splicing regulation, but also reveal a group of mis-spliced mRNA isoforms for potential therapeutic targeting. Overall design: Examination of differentially spliced events in K562 CRISPR cell clones (with wild-type or mutant SRSF2) by RNA sequencing
Disease-associated mutation in SRSF2 misregulates splicing by altering RNA-binding affinities.
No sample metadata fields
View SamplesGlioblastomas (GBMs) are divided into CpG Island Methylator Phenotype (CIMP) and non-CIMP tumors. Non-CIMP GBMs derive from cells with non-disjunction of chromosome (chr7) and chromosome 10 (chr10), resulting in chr7 gain and chr10 loss, while CIMP GBMs have mutations in isocitrate dehydrogenase 1 or 2 (IDH1/2). Gain of chr7 is largely driven by PDGFA, but other genes on chr7 are likely to contribute to fitness gains and aggressiveness of these GBMs. We computationally investigated genes on chr7 whose gene expression correlated with survival, identifying HOXA5 as a potential driver of proneural gliomagenesis. Using a combination of human GBM cells and mouse PDGF-driven gliomas, we showed that HOXA5 drives increased proliferation and radiation resistance in culture and in vivo. These phenotypes appear to be in part due to effects on p53 and other apoptosis-related genes.
Increased <i>HOXA5</i> expression provides a selective advantage for gain of whole chromosome 7 in IDH wild-type glioblastoma.
Disease
View SamplesThe effect of Tlr4P712H mutation (rendering TLR4 non-functional), or gut-sterilization by antbiotics, on the induction of tumorgenesis by CCl4 and diethylnitrosamine (DEN) was characterized. Affymetrix Mouse 430 2.0 gene expression measurements were used to characterize the transcriptomic basis of the effects of the above treatments and genotypes on tumorgenesis.
Promotion of hepatocellular carcinoma by the intestinal microbiota and TLR4.
Sex, Age, Specimen part
View SamplesThe gene expression of mice with osteoblast-specific beta-catenin activation or FoxO1 deactivation are each compared to that of Wt.
Leukaemogenesis induced by an activating β-catenin mutation in osteoblasts.
Sex, Specimen part
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Extrinsic Phagocyte-Dependent STING Signaling Dictates the Immunogenicity of Dying Cells.
Specimen part, Cell line
View SamplesThe ability of dying cells to activate antigen presenting cells (APCs) is carefully controlled to avoid unwarranted inflammatory responses. Here we show that engulfed cells only containing cytosolic dsDNA species (viral or synthetic) or cyclic di-nucleotides (CDNs) are able to stimulate APCs, via extrinsic STING-signaling.
Extrinsic Phagocyte-Dependent STING Signaling Dictates the Immunogenicity of Dying Cells.
Specimen part
View SamplesTransfected double strand DNA were required for the efficient activation of STING to activate innate immune cytokine.
Extrinsic Phagocyte-Dependent STING Signaling Dictates the Immunogenicity of Dying Cells.
Cell line
View SamplesThe transcription factor GATA2 regulates chemotherapy resistance in prostate cancer. We report a novel GATA2 transcriptional program that has implications for chemotherapy resistance disease and aggressiveness in castration resistant prostate cancer. Overall design: Examination of the transcriptional network changes induced in human Ch-CRPC cell lines by two shRNA mediated knock down of GATA2 versus random shRNA control
A targetable GATA2-IGF2 axis confers aggressiveness in lethal prostate cancer.
No sample metadata fields
View SamplesThis SuperSeries is composed of the SubSeries listed below.
The B-cell receptor controls fitness of MYC-driven lymphoma cells via GSK3β inhibition.
No sample metadata fields
View Samples