CRISPR-mediated mutagenesis of RNA editing cis-regulatory elements
Ontology highlight
ABSTRACT:
ORGANISM(S): synthetic construct Homo sapiens
PROVIDER: GSE138860 | GEO | 2020/06/01
REPOSITORIES: GEO
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Project description:RNA-seq of Colon cancer cell line Sw480 with Ajuba OE and KD.Colon cancer, along with its potential for recurrence and metastasis is a major health problem. Understanding the proteins and pathways that regulate cell growth and metastasis may provide new targets for patient care. Ajuba is a LIM domain protein often found overexpressed in cancers, however the exact function role of Ajuba in colon cancer is not known. Our data demonstrates that Ajuba is highly expressed in colon cancer cell lines and tumour tissue compared to adjacent non-tumour tissue. Using publicly available data from The Cancer Genome Atlas, we correlated poor colon cancer patient survival with high Ajuba expression. To investigate the function of Ajuba in colon cancer metastasis we transduced cells with lentiviral constructs to knock down and overexpress Ajuba protein and performed an RNA-seq transcriptomic analysis on each modified line. Analysing the pathways enriched in the differentially expressed genes, we found Ajuba to be involved in cell proliferation, migration and differentiation. We confirmed our findings in biological assays, cells depleted of Ajuba were less proliferative, more sensitive to irradiation, migrated less and were less efficient in colony formation. Our data indicates that increased Ajuba expression observed in colon cancer supports proliferation, epithelial-to-mesenchymal transition and metastasis.
2020-07-25 | GSE147111 | GEO
Project description:Alternative splicing and mRNA editing are known to contribute to transcriptome diversity. Although alternative splicing is pervasive and known to contribute to a variety of pathologies, including cancer, the genetic context for individual differences in isoform usage is still evolving. Similarly, although mRNA editing is ubiquitous and associated with important biological processes such as intracellular viral replication and cancer development, individual variations in and the genetic transmissibility of mRNA editing are equivocal. Here, we have used linkage analysis to show that both mRNA editing and alternative splicing are regulated by the macrophage genetic background and environmental cues. We show that distinct loci, potentially harboring variable splice factors, regulate the splicing of multiple transcripts. Additionally, we show that individual genetic variability at the Apobec1 locus results in differential rates of C-to-U(T) editing in murine macrophages; with mouse strains expressing mostly a truncated isoform of Apobec1 exhibiting lower rates of editing. As a proof of concept, we have used linkage analysis to identify 36 high confidence novel edited sites. These results provide a novel and complementary method that can be used to identify C-to-U editing sites in individuals segregating at specific loci and show that, beyond individual DNA sequence and structural changes, differential isoform usage and mRNA editing can contribute to intra-species genomic and phenotypic diversity. Bone marrow derived macrophages (BMDM) from female AxB/BxA mice were left unstimulated or stimulated with IFNG/TNF, or CpG for 18 hrs or infected with infected with type II (Pru A7) for 8 hrs. The transcriptional response was then measured using the illumina RNA-seq protocol on an illumuna HiSeq 2000.
2013-11-13 | E-GEOD-47540 | biostudies-arrayexpress
Project description:Adenosine-to-inosine (A-to-I) RNA editing catalyzed by ADAR enzymes occurs in double-stranded RNAs. Despite a compelling need towards predictive understanding of natural and engineered editing events, how the RNA sequence and structure determine the editing efficiency and specificity (i.e., cis-regulation) is poorly understood. We apply a CRISPR/Cas9-mediated saturation mutagenesis approach to generate libraries of mutations near three natural editing substrates at their endogenous genomic loci. We use machine learning to integrate diverse RNA sequence and structure features to model editing levels measured by deep sequencing. We confirm known features and identify new features important for RNA editing. Training and testing XGBoost algorithm within the same substrate yield models that explain 68 to 86 percent of substrate-specific variation in editing levels. However, the models do not generalize across substrates, suggesting complex and context-dependent regulation patterns. Our integrative approach can be applied to larger scale experiments towards deciphering the RNA editing code.
2021-03-05 | GSE168234 | GEO
Project description:Background and Aims: The LIM protein AJUBA participates in the regulation of cell adhesion, mitosis, DNA damage, cell differentiation, proliferation, migration and gene transcription, yet its roles in tumor development and progression are poorly defined. The aim is to determine the role of AJUBA in colorectal tumorigenesis. Methods: We performed data mining in Oncomine databases and immunohistochemistry (IHC) assays on 67 paired colorectal cancer (CRC) samples; we manipulated the AJUBA expression in SW-1116 and Caco-2 cells using specific shRNA and overexpression plasmids and performed assays for cell viability, cell cycle and apoptosis; we performed RNA-seq and qRT-PCR assays to identify genes regulated by AJUBA; we performed western blot, co-immunoprecipitation assays to study the interaction of AJUBA and JAK/STAT; Results: We discovered that AJUBA is highly expressed in CRC and promotes CRC cell growth in culture and in xenograted mice via an inhibition of apoptosis by repression of the IFIT2 gene. AJUBA specifically binds the FERM domain of JAK1 to dissociate JAK1 from the IFNγ recepter, resulted in inhibition of STAT1 phosporylation and concomitantly its nuclear translocation. Clinically, the level of AJUBA in CRC specimens is negatively correlated with the levels of IFIT2 and pSTAT1. Conclusion: Ajuba functions as a specific suppressor of the Interferon-activated JAK1/STAT1 signaling to promote colorectal cancer development via an inhibition of Interferon induced apoptosis.
2017-02-23 | GSE84902 | GEO
Project description:RNA editing is a mutational mechanism that specifically alters the nucleotide content in sets of transcripts while leaving their cognate genomic blueprint intact. Editing has been detected from bulk RNA-seq data in thousands of distinct transcripts, but apparent editing rates can vary widely (from under 1% to almost 100%). These observed editing rates could result from approximately equal rates of editing within each individual cell in the bulk sample, or alternatively, editing estimates from a population of cells could reflect an average of distinct, biologically significant editing signatures that vary substantially between individual cells in the population. To distinguish between these two possibilities we have constructed a hierarchical Bayesian model which quantifies the variance of editing rates at specific sites using RNA-seq data from both single cells and a cognate bulk sample consisting of ∼ 106 cells. The model was applied to data from murine bone-marrow derived macrophages and dendritic cells, and predicted high variance for specific edited sites in both cell types tested. We then 1 validated these predictions using targeted amplification of specific editable transcripts from individual macrophages. Our data demonstrate substantial variance in editing signatures between single cells, supporting the notion that RNA editing generates diversity within cellular populations. Such editing-mediated RNA-level sequence diversity could contribute to the functional heterogeneity apparent in cells of the innate immune system.
2016-07-11 | GSE74720 | GEO
Project description:HDMYZ cells were treated with 2ug/ml ActD for 0, 4 and 12 hours. Small RNAs of 15-40 bases were gel-purified from 10 ug total RNA, and subjected to multiplex Illumina small RNA library preparation. Small RNA libraries were sequenced on a HiSeq2000 (Illumina) with 3 samples per lane. To quantify miRNA and isoform abundance, sequence reads were processed by the miRDeep2 package, with the following modifications. First, to remove adaptor sequence, we removed both the main adaptor sequence present in the sequencing reads, as well as the second most abundant adaptor variant. In addition, we did not restrict the size of small RNAs during adaptor removal. Second, we used miRBase v18 for mapping the reads. Third, for quantifying miRNA and isoform frequency, we limited reads to more or equal to 15 bases in length with zero mis-match during mapping. The number of reads that were mapped to known miRNAs was used to normalize read frequencies for each miRNA or each miRNA isoform. For quantification purposes, we only considered miRNAs or isoforms that had frequency >= 1x10e-6 in samples without ActD treatment, which correspond to ~21-30 reads in raw count. These miRNAs or isoforms were referred to as reliably quantifiable.To analyze mapping to the genome, we removed reads that mapped to miRNA precursors. The rest of the reads were then mapped to the genome with Bowtie.
2017-09-02 | GSE46968 | GEO
Project description:Alternative splicing (AS) influences the expression of human genes in diverse ways. We previously used subcellular fraction-sequencing (Frac-Seq) to reveal an unexpected connection between alternative splicing and isoform-specific mRNA translation. Here we apply comparative transcriptomics to explore alternative splicing coupled translational control (AS-TC) across 13 million years of primate evolution. We used Frac-seq to identify polyribosome associated mRNA isoforms from human, chimpanzee and orangutan induced pluripotent stem cell lines. We discovered orthologous AS-TC events with either conserved or species-specific translation patterns. Exons sequences associated with similar sedimentation profiles between species show strong sequence conservation compared to orthologous exons with divergent sedimentation profiles, suggesting exonic cis-regulatory elements influence to translational control. To test this hypothesis we created luciferase reporters from orthologous exons with divergent sedimentation profiles differing by a single nucleotide. Remarkably, single nucleotide substitutions were sufficient to drive species-specific expression of luciferase reporters. Together these data establish that cis-acting elements regulate AS-TC across primate species.
2024-04-30 | GSE230441 | GEO
Project description:Although genetic studies have identified many hundreds of loci associated with human traits and diseases, pinpointing the causal alleles remains difficult, particularly for non-coding variants. To address this challenge, we have enhanced the sensitivity and reproducibility of the massively parallel reporter assay (MPRA), adapting it to identify variants that directly modulate gene expression. We then applied it to over 29,000 single nucleotide and insertion/deletion polymorphisms from 3,965 cis-expression quantitative trait loci (eQTL). We demonstrate strong correlation between our MPRA approach and existing measures of regulatory function, and determine an approximate sensitivity of ~20% with a positive predictive value of 60-65% to detect an eQTL causal allele. We identify 842 variants showing differential expression between alleles, including 53 well-annotated variants associated with diseases and traits. Thus, we have created a resource of concrete leads for understanding the genetic basis of specific phenotypes and illustrate the promise of this kind of approach for comprehensively interrogating how non-coding polymorphism shapes human biology. The study consists of two separate MPRA experiments, a 78,958 oligo (79k study) and a 7,500 oligo library (7.5k). For each library we processed independent transfections into two lymphoblastoid cell lines; in total we completed 5 replicates of NA12878 and 3 replicates of NA19239. For the 79k library we also performed 5 replicate transfections into the hepatocarcinoma cell line HepG2. Raw data is provided as Illumina reads of the 20 bp barcode from the RNA extracted 24 hours post transfection as well as from the plasmid library used for transfection. We also provide oligo/barcode combinations from the âgfp vector in the form of a tab delimited file containing the raw sequence reads of the barcode (column 1) and genomic sequence (column 2). Processed count files are unnormalized counts for each oligo acquired by summing all barcode matches together for each replicate.
2016-06-01 | E-GEOD-75661 | biostudies-arrayexpress
Project description:Background: RNA editing encompasses a post-transcriptional process in which the genomically templated sequence is enzymatically altered and introduces a modified base into the edited transcript. Mammalian C-to-U RNA editing represents a distinct subtype of base modification, whose prototype is intestinal apolipoproteinB (apoB) mRNA, mediated by the catalytic deaminase Apobec-1. However, the genome-wide identification, tissue-specificity and functional implications of Apobec-1 mediated C-to-U RNA editing remains incomplete. Results: Deep sequencing, data filtering and Sanger-sequence validation of intestinal and hepatic RNA from wild-type and Apobec-1 deficient mice revealed 56 novel editing sites in 54 intestinal mRNAs and 22 novel sites in 17 liver mRNAs (74-81% Sanger sequenced validated), all within 3’ untranslated regions. Eleven of 17 liver RNAs shared editing sites with intestinal RNAs, while 6 sites were unique to liver. Changes in RNA editing led to corresponding changes in intestinal mRNA and protein levels in 11 genes. RNA editing in vivo following tissue-specific Apobec-1 adenoviral or transgenic Apobec-1 overexpression revealed that a subset of targets identified in wild-type mice were restored in Apobec-1 deficient mouse intestine and liver following Apobec-1 rescue. We found distinctive polysome profiles for several RNA editing targets and demonstrated novel exonic editing sites in nuclear preparations from intestine (but not hepatic) apoB RNA. RNA editing was validated using cell-free extracts from wild-type but not Apobec-1 deficient mice, demonstrating that Apobec-1 is required. Conclusions: These studies define selective, tissue-specific targets of Apobec-1 dependent RNA editing and show the functional consequences of editing are both transcript- and tissue-specific.
2014-06-02 | PXD001007 | Pride
Project description:Adenosine deaminase acting on RNA (ADAR) (also known as ADAR1) promotes A-to-I conversion in double-stranded and highly structured RNAs. ADAR1 has two isoforms transcribed from different promoters: ADAR1p150, which is mainly cytoplasmic and interferon-inducible, and constitutively expressed ADAR1p110 that is primarily localized in the nucleus. Mutations in ADAR1 cause Aicardi – Goutières syndrome (AGS), a severe autoinflammatory disease in humans associated with aberrant IFN production. In mice, deletion of ADAR1 or selective knockout of the p150 isoform alone leads to embryonic lethality driven by overexpression of interferon-stimulated genes. This phenotype can be rescued by concurrent deletion of cytoplasmic dsRNA-sensor MDA5. These findings indicate that the interferon-inducible p150 isoform is indispensable and cannot be rescued by the ADAR1p110 isoform. Nevertheless, editing sites uniquely targeted by ADAR1p150 but also mechanisms of isoform- specificity remain elusive. To identify ADAR1 isoform-specific ‘editome’, we transfected A-to-I editing deficient mouse embryonic fibroblasts (MEFs) with ADAR1p150- or ADAR1p110- or RFP-editing negative control. We subjected the samples to RNA sequencing and detected editing at known-editing sites.
2021-11-17 | GSE188842 | GEO