The RAG1 endonuclease, together with its cofactor RAG2, is essential for V(D)J recombination but is a potent threat to genome stability. The sources of RAG1 mistargeting and the mechanisms that have evolved to suppress it are poorly understood. Here, we report the surprising finding that RAG1 binds to thousands of sites in the genome of developing lymphocytes, primarily at active promoters and enhancers. The genome has responded by reducing the abundance of "cryptic" recombination signals near sites of RAG1 binding. This depletion operates specifically on the RSS heptamer, with nonamers enriched at RAG1 binding sites. Reversing this RAG-driven depletion of cleavage sites by insertion of strong recombination signals creates an ectopic hub of RAG-mediated V(D)J recombination and chromosomal translocations. Our findings delineate rules governing RAG binding in the genome, identify areas at risk of RAG-mediated damage, and highlight the evolutionary struggle to accommodate programmed DNA damage in developing lymphocytes. Overall design: RNA-seq profiles of mouse thymocytes
RAG Represents a Widespread Threat to the Lymphocyte Genome.
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View SamplesTo normalize transcriptome data we combined total RNA isolated from 10^6 resting or activated B cells with 1 µl of 1/10 dilution of Ambion’s ERCC RNA Spike-in Mix (92 mRNA standards). mRNA was then isolated and processed following Illumina’s RNA-seq protocol v2.
Global regulation of promoter melting in naive lymphocytes.
Specimen part, Cell line
View SamplesBirt-Hogg-Dube (BHD) syndrome is an autosomal dominant disorder characterized by hamartomas of skin follicles, cystic lung disease, and renal neoplasia. Affected individuals carry heterozygous mutations in Folliculin (FLCN), a tumor suppressor gene that becomes biallelically inactivated in kidney tumors by second-hit mutations. Similar to other factors implicated in kidney malignancies, Folliculin has been shown to modulate activation of mammalian target of rapamycin (mTOR). However, its precise in vivo function is largely unknown because germline deletion of Flcn results in early embryonic lethality in animal models. We here describe mice deficient in the newly characterized Folliculin-Interacting Protein 1 (Fnip1). In contrast to Flcn, Fnip1-/- mice develop normally, are not susceptible to kidney neoplasia, but display a striking pro-B cell block that is independent of mTOR activity. We show that this developmental arrest results at least in part from impaired V(D)J recombination and caspase-induced cell death, and that pre-recombined V(D)J and Bcl2 transgenes reconstitute pre-B and mature B cell populations respectively. We also demonstrate that conditional deletion of Flcn recapitulates the pro-B cell arrest of Fnip1-/- mice. Our studies thus demonstrate that the Flcn-Fnip complex deregulated in BHD syndrome is absolutely required for B cell differentiation and that it functions both through mTOR dependent and independent pathways. Overall design: RNASeq data for two pro-B cell subsets (fraction B and CC'') isolated from wt and Fnip1-/- mice
The folliculin-FNIP1 pathway deleted in human Birt-Hogg-Dubé syndrome is required for murine B-cell development.
Cell line, Subject
View SamplesExpression data from Breast cancer subtypes
Chronic oxidative stress promotes H2AX protein degradation and enhances chemosensitivity in breast cancer patients.
Disease, Cell line
View SamplesIn a cohort study of 7 women with primary invasive breast cancer, we obtained a tumor specimen before (biopsy) and after (tumorectomy) 4 cycles of NAC with epirubicine and cyclophosphamide, followed by 4 cycles of taxanes. Total RNA was extracted from tumor specimens and the whole transcriptome was quantified with Affymetrix HuGene1.1ST. Molecular functions changing during chemotherapy were searched.
Chronic oxidative stress promotes H2AX protein degradation and enhances chemosensitivity in breast cancer patients.
Specimen part, Subject, Time
View Samples10 biopsies before treatment from triple negative patients with complete response were collected. Total RNA was extracted from tumor specimens and the whole transcriptome was quantified with Affymetrix HuGene1.1ST. The biopsies were classified into Good (major or complete) or Poor (absent or minor) therapeutic response subgroup.
Chronic oxidative stress promotes H2AX protein degradation and enhances chemosensitivity in breast cancer patients.
Sex, Specimen part
View SamplesImmuno-chemotherapy regimens elicit high response rates in B-cell non-Hodgkin lymphoma but heterogeneity in response duration is observed, with some patients achieving cure and others showing refractory disease or relapse. Using a transcriptome-powered targeted proteomics screen, we discovered a gene regulatory circuit involving the nuclear factor CYCLON which characterizes aggressive disease and resistance to the anti-CD20 monoclonal antibody, Rituximab, in high-risk B-cell lymphoma. CYCLON knockdown was found to inhibit the aggressivity of MYC-overexpressing tumors in mice and to modulate gene expression programs of biological relevance to lymphoma. Furthermore, CYCLON knockdown increased the sensitivity of human lymphoma B cells to Rituximab in vitro and in vivo. Strikingly, this effect could be mimicked by in vitro treatment of lymphoma B cells with a small molecule inhibitor for BET bromodomain proteins (JQ1). In summary, this work has identified CYCLON as a new MYC cooperating factor that drives aggressive tumor growth and Rituximab resistance in lymphoma. This resistance mechanism is amenable to next-generation epigenetic therapy by BET bromodomain inhibition, thereby providing a new combination therapy rationale for high-risk lymphoma.
Identification of a novel BET bromodomain inhibitor-sensitive, gene regulatory circuit that controls Rituximab response and tumour growth in aggressive lymphoid cancers.
Specimen part, Cell line
View SamplesWe define the effects of reduced insulin production in beta-cells from tamoxifen-treated Ins1-/-:Ins2f/f:Pdx1CreERT:mTmG mice studied at a time point when insulin production was reduced by ~50%. Overall design: Examination of the transcriptome of adult pancreatic islets from mice with acute Ins2 gene knockout out on an Ins1 null background
Reduced Insulin Production Relieves Endoplasmic Reticulum Stress and Induces β Cell Proliferation.
Specimen part, Treatment, Subject
View SamplesRNA-sequencing (RNA-seq) measures RNA abundance in a biological sample but does not provide temporal information about the sequenced RNAs. Metabolic labeling can be used to distinguish newly made RNAs from pre-existing RNAs. Mutations induced from chemical recoding of the hydrogen bonding pattern of the metabolic label can reveal which RNAs are new in the context of a sequencing experiment. These nucleotide recoding strategies have been developed for a single uridine analogue, 4-thiouridine (s4U), limiting the scope of these experiments. Here we report expansion of TimeLapse sequencing (TimeLapse-seq) to the guanosine analogue, 6-thioguanosine (s6G), which can be recoded under RNA-friendly nucleophilic-aromatic substitution conditions to produce adenine analogues (substituted 2-aminoadenosines). We demonstrate the first use of s6G recoding experiments to reveal transcriptome-wide RNA population dynamics. Overall design: Distinguishing newly made from preexising RNA using RNA-sequencing of 6-thioguanosine containing RNA, which was subjected to TimeLapse chemistry to induce G to A mutations in newly-made RNA.
Expanding the Nucleoside Recoding Toolkit: Revealing RNA Population Dynamics with 6-Thioguanosine.
Cell line, Treatment, Subject
View SamplesEpstein Barr virus (EBV) nuclear antigen 3C (EBNA3C) is an essential transcription factor for initiating and maintaining human B lymphocyte transformation to lymphoblastoid cell lines (LCLs). To comprehensively identify EBNA3C regulated cell genes in LCLs, oligonucleotide arrays were used to compare RNA abundances in 3 different LCLs transformed by an EBV that conditionally expresses EBNA3C. Cell RNA levels were assessed in actively growing LCLs, under non-permissive or permissive conditions or under non-permissive conditions after transcomplementation with wild type EBNA3C. A two-way ANOVA model with covariates including the 3 different clone effects and the 3 EBNA3C expression levels, identified 550 EBNA3C regulated genes, with False Discovery Rate <0.01 and >1.5 fold change. A seeded Bayesian network analysis of the 80 most significantly EBNA3C regulated genes that changed >1.5 fold, positioned RAC1, LYN and TNF upstream of other EBNA3C regulated genes. Further, Gene Set Enrichment Assay (GSEA) identified EBNA3C regulated genes to be enriched for MAP kinase signaling, cytokine-cytokine receptor interactions, JAK-STAT signaling, and cell adhesion molecule effects, implicating these pathways in LCL growth or survival. Moreover, 106 EBNA3C regulated genes could be placed in protein interaction networks. Since CXCL12 and CXCR4 signaling are implicated in LCL growth and were EBNA3C up-regulated, up-regulation of CXCL12 was validated by qRT-PCR and effects on induced LCL migration were confirmed. EBNA3C regulated genes significantly overlapped with EBNA2 and EBNA3A regulated genes, consistent with a central role for RBP/CSL in these effects.
Epstein-Barr virus nuclear antigen 3C regulated genes in lymphoblastoid cell lines.
Specimen part
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