Project description:Adenosine deaminase acting on RNA 1 (ADAR1), is an enzyme that catalyzes the conversion of adenosine to inosine in double-stranded RNA, a process critical for regulation of innate immune response and distinguishing between ‘self and non-self RNA’. It is expressed as two isoforms: nucleolar p110 and cytoplasmic, interferon (IFN)-inducible, p150. The interactome of the p110 under steady-state conditions is well-studied; however, less is known about the interactions of the p150 isoform, particularly during IFN response. To elucidate ADAR1's protein interactions during IFN stimulation, alongside steady-state conditions, three distinct methods of enrichment were used followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). These included: immunoprecipitation (IP) of endogenous ADAR1, IP of Strep II-tagged ADAR1, and proximity labeling using BioID. Individual ADAR1 isoforms (p110 and p150) and their respective dsRNA binding-deficient mutants were created to discern isoform-specific and dsRNA-dependent interactions. Altogether, our results reveal a comprehensive ADAR1 interaction map, identifying both known and novel partners, and highlighting the isoform-specific and dsRNA-binding-dependent nature of ADAR1 interactions. Under IFN stimulation, ADAR1's interaction spectrum encompasses viral replication inhibitors and LINE-1 regulators. Mimicking viral infection with HMW poly(I:C) changed the proximal network of proteins for both isoforms. Our findings provide new insights into ADAR1's roles and its dynamic during IFN response.
Project description:Adenosine deaminase acting on RNA 1 (ADAR1), is an enzyme that catalyzes the conversion of adenosine to inosine in double-stranded RNA, a process critical for regulation of innate immune response and distinguishing between ‘self and non-self RNA’. It is expressed as two isoforms: nucleolar p110 and cytoplasmic, interferon (IFN)-inducible, p150. The interactome of the p110 under steady-state conditions is well-studied; however, less is known about the interactions of the p150 isoform, particularly during IFN response. To elucidate ADAR1's protein interactions during IFN stimulation, alongside steady-state conditions, three distinct methods of enrichment were used followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). These included: immunoprecipitation (IP) of endogenous ADAR1, IP of Strep II-tagged ADAR1, and proximity labeling using BioID. Individual ADAR1 isoforms (p110 and p150) and their respective dsRNA binding-deficient mutants were created to discern isoform-specific and dsRNA-dependent interactions. Altogether, our results reveal a comprehensive ADAR1 interaction map, identifying both known and novel partners, and highlighting the isoform-specific and dsRNA-binding-dependent nature of ADAR1 interactions. Under IFN stimulation, ADAR1's interaction spectrum encompasses viral replication inhibitors and LINE-1 regulators. Mimicking viral infection with HMW poly(I:C) changed the proximal network of proteins for both isoforms. Our findings provide new insights into ADAR1's roles and its dynamic during IFN response.
Project description:Adenosine deaminase acting on RNA 1 (ADAR1), is an enzyme that catalyzes the conversion of adenosine to inosine in double-stranded RNA, a process critical for regulation of innate immune response and distinguishing between ‘self and non-self RNA’. It is expressed as two isoforms: nucleolar p110 and cytoplasmic, interferon (IFN)-inducible, p150. The interactome of the p110 under steady-state conditions is well-studied; however, less is known about the interactions of the p150 isoform, particularly during IFN response. To elucidate ADAR1's protein interactions during IFN stimulation, alongside steady-state conditions, three distinct methods of enrichment were used followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). These included: immunoprecipitation (IP) of endogenous ADAR1, IP of Strep II-tagged ADAR1, and proximity labeling using BioID. Individual ADAR1 isoforms (p110 and p150) and their respective dsRNA binding-deficient mutants were created to discern isoform-specific and dsRNA-dependent interactions. Altogether, our results reveal a comprehensive ADAR1 interaction map, identifying both known and novel partners, and highlighting the isoform-specific and dsRNA-binding-dependent nature of ADAR1 interactions. Under IFN stimulation, ADAR1's interaction spectrum encompasses viral replication inhibitors and LINE-1 regulators. Mimicking viral infection with HMW poly(I:C) changed the proximal network of proteins for both isoforms. Our findings provide new insights into ADAR1's roles and its dynamic during IFN response.
Project description:The purpose of this study was to examine the role of ZBP1 in the phenotype that develops when ADAR1 activity is missing, in particular when the Zα domain of ADAR1 is mutated. Mice homozygous for a Zα domain-mutant allele of Adar1 (Adar1mZα/mZα mice) were compared with control mice carrying one mZα allele and one wild type allele of Adar1 (Adar1wt/mZα mice) and with mice carrying one mZα and one null Adar1 allele (Adar1-/mZα mice). Adar1-/mZα mice were also compared with mice additionally deficient in ZBP1 (Adar1-/mZα Zbp1-/- mice). Given the early postnatal lethal phenotype that develops in Adar1-/mZα mice, comparisons were made in RNA isolated from spleen tissue from newborn mice of each genotype (5 mice per genotype).
Project description:Aberrant RNA-editing was observed in several human tumors, but its significance is mostly unknown. Here we show that ADAR1, a ubiquitous RNA-editing enzyme, is commonly lost in metastatic melanoma cells and specimens. Experimental ADAR1 silencing significantly alters melanoma cell morphology, facilitates proliferation and cell-cycle, and increases the tumorigenicity in-vivo. A series of ADAR1 truncation mutants establishes a novel RNA-editing-independent role for ADAR1 in controlling the nuclear and cytoplasmic processing steps of miRNA biogenesis. Altered expression of ADAR1-controled miRNAs accounts for the observed phenotype. We show that the oncogenic miR-17-5p endogenously regulates ADAR1 expression and that its genomic sequence is frequently amplified in melanoma to overexpress the mature miR-17-5p form. ADAR1 and miR-17-5p are ubiquitously expressed, suggesting the generality of this mechanism. Melanoma cell line expressing low ADAR1 levels (ADAR1-Knockdown) using shRNA technique were selected for RNA extraction and hybridization on Affymetrix microarrays. We sought to examine the alterations in the genes and microRNA expression profile in the manipulated cell system, due to ADAR1 possible involvement cancer development. To that end, we selected ADAR1-knockdown (ADAR1-KD) cells that demonstrated an enhanced aggressive phenotype both in vivo and in vitro as compared to the control cells (Control).
Project description:The purpose of this study was to examine the role of MAVS and ZBP1 in the phenotype that develops when ADAR1 activity is missing, in particular when the Za domain of ADAR1 is mutated. Mice homozygous for a Za domain-mutant allele of Adar1 (Adar1mZa/mZa mice) were compared with control mice carrying one mZa allele and one wild type allele of Adar1 (Adar1wt/mZa mice) and with mice carrying one mZa and one null Adar1 allele (Adar1-/mZa mice). Adar1-/mZa mice were also compared with mice additionally deficient in ZBP1 (Adar1-/mZa Zbp1-/- mice) or MAVS (Adar1-/mZa Mavs-/- mice). Given the early postnatal lethal phenotype that develops in Adar1-/mZa mice, comparisons were made in RNA isolated from brain tissue from newborn mice of each genotype (4 mice per genotype).
Project description:RNAseq analysis of cell lines with ADAR1-p150 and ADAR1-p110 knock-outs and primary human tissue samples (from GSE57353 and GSE99392 data sets) to identify sites of ADAR1 editing
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 purpose of this study was to examine the role of MAVS, ZBP1 and RIPK3 in the phenotype that develops when ADAR1 activity is impaired, in particular when the Za domain of ADAR1 is mutated. Mice homozygous for a Za domain-mutant allele of Adar1 (Adar1mZa/mZa mice) and mice carrying one mZa and one null Adar1 allele (Adar1-/mZa mice) were compared with control mice that were either wild type or heterozygous for the Adar1 mZa allele (Adar1wt/mZa mice). The effects of MAVS deficiency, RIPK3 deficiency, ZBP1 deficiency or ZBP1 Za domain mutations were assessed by analysing compound mutant mice. Given the early postnatal lethal phenotype that develops in Adar1-/mZa mice, comparisons were made in RNA isolated from lung tissue from newborn mice of each genotype (5 mice per genotype). As Adar1-/mZa mice additionally lacking Mavs or Zbp1 are viable, adult mice (15-20 weeks of age) were also used for several compound mutations as donors of lung tissue.