RNA Sequencing Quantitative Analysis and identification of RNA editing sites of Wild Type and ADAR1 editing deficient (ADAR1E861A) murine fetal liver RNA
ABSTRACT: Purpose: RNA editing by ADAR1 is essential for hematopoietic development. The goals of this study were firstly, to identify ADAR1-specific RNA-editing sites by indentifying A-to-I (G) mismatches in RNA-seq data compared to mm9 reference genome in wild type mice that were not edited or reduced in editing frequency in ADAR1E861A editing deficient mice. Secondly, to determine the transcriptional consequence of an absence of ADAR1-mediated A-to-I editing. Methods: Fetal liver mRNA profiles of embryonic day 12.5 wild-type (WT) and ADAR1 editing-deficient (ADAR1E861A) mice were generated by RNA sequencing, in triplicate (biological replicates), using Illumina HiSeq2000. The sequence reads that passed quality filters were analyzed at the transcript level with TopHat followed by Cufflinks. qRT–PCR validation was performed using SYBR Green assays. A-to-I (G) RNA editing sites were identified as previously described by Ramaswami G. et al., Nature Methods, 2012 using Burrows–Wheeler Aligner (BWA) followed by ANOVA (ANOVA). RNA editing sites were confirmed by Sanger sequencing. Results: Using an optimized data analysis workflow, we mapped about 30 million sequence reads per sample to the mouse genome (build mm9) and identified 14,484 transcripts in the fetal livers of WT and ADAR1E861A mice with BWA. RNA-seq data had a goodness of fit (R2) of >0.94 between biological triplicates per genotype. Approximately 4.4% of the transcripts showed differential expression between the WT and ADAR1E861A fetal liver, with a LogFC≥1.5 and p value <0.05. A profound upregulation of interferon stimulated genes were found to be massively upregulated (up to 11 logFC) in ADAR1E861A fetal liver compared to WT. 6,012 A-to-I RNA editing sites were identified when assessing mismatches in RNA-seq data of WT and ADAR1E861A fetal liver. Conclusions: Our study represents the first detailed analysis of fetal liver transcriptomes and A-to-I RNA editing sites, with biologic replicates, generated by RNA-seq technology. A-to-I RNA editing is the essential function of ADAR1 and is required to suppress interferon signaling to endogenous RNA. Fetal liver mRNA profiles of E12.5 wild type (WT) and ADAR E861A mutant mice were generated by deep sequencing, in triplicate, using Illumina HiSeq 200.
Project description:Purpose: RNA editing by ADAR1 is essential for hematopoietic development. The goals of this study were firstly, to identify ADAR1-specific RNA-editing sites by indentifying A-to-I (G) RNA editing sites in wild type mice that were not edited or reduced in editing frequency in ADAR1 deficient murine erythroid cells. Secondly, to determine the transcription consequence of an absence of ADAR1-mediated A-to-I editing. Methods: Total RNA from E14.5 fetal liver of embryos with an erythroid restricted deletion of ADAR1 (KO) and littermate controls (WT), in duplicate. cDNA libraries were prepared and RNA sequenced using Illumina HiSeq2000. The sequence reads that passed quality filters were analyzed at the transcript level with TopHat followed by Cufflinks. qRT–PCR validation was performed using SYBR Green assays. A-to-I (G) RNA editing sites were identified as previously described by Ramaswami G. et al., Nature Methods, 2012 using Burrows–Wheeler Aligner (BWA) followed by ANOVA (ANOVA). RNA editing sites were confirmed by Sanger sequencing. Results: Using an optimized data analysis workflow, we mapped about 30 million sequence reads per sample to the mouse genome (build mm9) and identified 14,484 transcripts in the fetal livers of WT and ADAR1E861A mice with BWA. RNA-seq data had a goodness of fit (R2) of >0.7, p<0.0001 between biological duplicates per genotype. Clusters of hyper-editing were onserved in long, unannotated 3'UTRs of erythroid specific transcripts. A profound upregulation of interferon stimulated genes were found to be massively upregulated (up to 5 log2FC) in KO fetal liver compared to WT. 11.332 (6,894 novel) A-to-I RNA editing sites were identified when assessing mismatches in RNA-seq data. Conclusions: Our study represents the first detailed analysis of erythroid transcriptomes and A-to-I RNA editing sites, with biologic replicates, generated by RNA-seq technology. A-to-I RNA editing is the essential function of ADAR1 and is required to prevent sensing of endogenous transcripts, likely via a RIG-I like receptor mediated axis. Fetal liver mRNA profiles of E14.5 wild type (WT) and ADAR Epor-Cre knock out mice were generated by deep sequencing, in duplicate using Illumina HiSeq 2000.
Project description:The genome-wide identification, tissue-specificity and functional implications of Apobec-1 mediated C-to-U RNA editing remains incomplete. Deep sequencing, data filtering and validation 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% true-positive), 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. We found distinctive polysome profiles for several editing targets and demonstrated nuclear but not cytoplasmic editing of novel exonic sites in intestinal (but not hepatic) apoB RNA. RNA editing was validated using cell-free extracts from wild-type but not Apobec-1 deficient mice. 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. Examination of C-to-U RNA editing in mouse liver and intestine
Project description:We used transgenic mouse embryos that are deficient in the two enzymatically active RNA editing enzymes ADAR1 and ADAR2 to compare relative frequencies but also sequence composition of mature miRNAs in these genetically modified backgrounds to wild-type mice by Illumina next gen sequencing. Deficiency of ADAR2 leads to a reproducible change in abundance of specific miRNAs and their predicted targets. Changes in miRNA abundance seem unrelated to editing events. Additional deletion of ADAR1 has surprisingly little impact on the mature miRNA repertoire, indicating that miRNA expression is primarily dependent on ADAR2. A to G transitions reflecting A to I editing events can be detected at few sites and at low frequency during the early embryonic stage investigated. Again, most editing events are ADAR2 dependent with only few editing sites being specifically edited by ADAR1. Besides known editing events in miRNAs a few novel, previously unknown editing events were identified. Some editing events are located to the seed region of miRNAs opening the possibility that editing leads to their retargeting. GSM852140-8: sequencing of mature miRNAs of wt, ADAR2-/- and ADAR1-/-/ADAR2-/- female mouse embryos at E11.5 GSM863778-81: Gene expression was measured in wiltype, ADAR2-/- and ADAR1-/-/ADAR2-/- E11.5 whole female mouse embryos using Agilent Whole Mouse Genome Oligo Microarrays 8x60K.
Project description:The ADAR RNA editing enzymes deaminate adenosine bases to inosines in cellular RNAs, recoding open reading frames. Human ADAR1 mutations cause Aicardi-Goutieres Syndrome (AGS) and Adar1 mutant mice showing an aberrant interferon response and death by embryonic day E12.5 model the human disease. Searches have not identified key ADAR1 RNA editing sites recoding immune/haematopoietic proteins but editing is widespread in Alu sequences. We show that Adar1 embryonic lethality is rescued in Adar1; Mavs double mutant mice in which general antiviral responses to cytoplasmic dsRNA are prevented. We propose that inosine bases are epigenetic marks identifying cellular RNA as innate immune ÒselfÓ. Consistent with this idea we show that an editing-active cytoplasmic ADAR is required to prevent aberrant immune responses in Adar1 mutant mouse embryo fibroblasts. No dramatic increase in repetitive transcripts is observed. AGS mutations in ADAR1 affect editing by the interferon-inducible cytoplasmic ADAR1 isoform. RNA-seq expression profiling in Adar1 and Adar1/Mavs knockout mice embryos.
Project description:The RNA editing enzyme ADAR chemically modifies adenosine (A) to inosine (I), which is interpreted by the ribosome as a guanosine. Here we assess cotranscriptional A-to-I editing in Drosophila, by isolating nascent RNA from adult fly heads and subjecting samples to high-throughput sequencing. There are a large number of edited sites within nascent exons. Nascent RNA from an ADAR null mutant strain was also sequenced, indicating that almost all A-to-I events require ADAR. Moreover, mRNA editing levels correlate with editing levels within the cognate nascent RNA sequence, indicating that the extent of editing is set cotranscriptionally. Surprisingly, the nascent data also identify an excess of intronic over exonic editing sites. These intronic sites occur preferentially within introns that are poorly spliced cotranscriptionally, suggesting a link between editing and splicing. We conclude that ADAR-mediated editing is more widespread than previously indicated and largely occurs cotranscriptionally. GSM914095: Fly genomic DNA sequencing. Sequenced on the Illumina GA II. GSM914102-GSM914113: Fly head nascent RNA profiles over 6 time points of a 12hr light:dark cycle in duplicate; sequenced on the Illumina GA II. GSM914114-GSM914119: Fly head nascent RNA profiles of yw, FM7, ADAR0 males in duplicate; sequenced on the HiSeq2000. GSM915213-GSM915214: Fly head mRNA profiles over 2 time points of a 12hr light:dark cycle; sequenced on the Illumina GA II. GSM915215-GSM915220: Fly head mRNA profiles over 6 time points of a 12hr light:dark cycle; paired-end sequenced on the Illumina GA II. GSM915221-GSM91526: Fly head mRNA profiles over 6 time points of a 12hr light:dark cycle; sequenced on the Illumina GA II.
Project description:This dataset is a part of a bigger work on RNA editing in D. melanogaster brain. We present Orbitrap spectra searched against a customized database of Drosophila proteome with introduction of variants provided by RNA editing. Three files reflect 3 technical replicates.
Project description:Alternative splicing greatly expands the proteomic diversity but its functional impact is often unclear. Here, we identify a highly conserved and temporally coordinated cell-type-specific splicing program, which is activated in part by ESRP2 during postnatal liver development. Consistent with failure of many neonatal-to-adult splicing transitions, Esrp2 null mice exhibit persistent expression of fetal markers and loss of mature hepatocyte characteristics. Conversely, ectopic expression of ESRP2 in immature mouse or human hepatocytes results in a reciprocal switch in splicing. Our findings define an essential role for ESRP2 in generation of conserved repertoires of adult splice isoforms that facilitate postnatal liver maturation. Mouse liver RNA was isolated with Trizol (Invitrogen). Hi-Seq libraries were prepared and paired-end 100bp Illumina sequencing was performed on mouse liver samples from different developmental stages.
Project description:ADARs are the primary factors underlying A-to-I editing in metazoans. We conducted the first global study of ADAR1-RNA interaction in human cells using CLIP-Seq. In contrast to the expected predominant binding of ADAR1 to Alu repeats, thousands of CLIP sites were located in non-Alu regions. This unexpectedly frequent non-Alu binding enabled discovery of transcriptome-wide functional and biophysical targets of ADAR1 in the regulation of mRNA processing including alternative 3' UTR usage and alternative splicing. In addition, a global analysis of ADAR1 binding to non-Alu regions also revealed its primary interaction with microRNA (miRNA) transcripts in the nucleus, which subsequently affected expression levels of mature miRNAs. A complex global picture was revealed regarding the dependence of this function on the double-stranded RNA binding domains or deaminase activity. Our study unfolded a broad landscape of the diverse functional roles of ADAR1. To identify ADAR binding dependent miRNA defferential expression profiles, U87MG cells were transfected with ADAR1 overexpression vector, RNA binding mutant (EAA and E912A), siRNA of ADAR1 or controls.
Project description:The Adar1 deaminase inactive mutant mouse tissue samples were obtain from the Walkley lab as described in http://www.ncbi.nlm.nih.gov/pubmed/26275108. We performed mmPCR-seq on the samples and measured the editing levels of. Overall design: Fetal mRNA profiles of E12.5 wild type (WT) and ADAR E861A mutant mice were generated by deep sequencing using Illumina HiSeq 2000.