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Molecules and Cells Jun 2023Deamination of adenine or cytosine in RNA, called RNA editing, is a constitutively active and common modification. The primary role of RNA editing is tagging RNA right...
Deamination of adenine or cytosine in RNA, called RNA editing, is a constitutively active and common modification. The primary role of RNA editing is tagging RNA right after its synthesis so that the endogenous RNA is recognized as self and distinguished from exogenous RNA, such as viral RNA. In addition to this primary function, the direct or indirect effects on gene expression can be utilized in cancer where a high level of RNA editing activity persists. This report identified actin-related protein 2/3 complex inhibitor (ARPIN) as a target of ADAR1 in breast cancer cells. Our comparative RNA sequencing analysis in MCF7 cells revealed that the expression of ARPIN was decreased upon ADAR1 depletion with altered editing on its 3'UTR. However, the expression changes of ARPIN were not dependent on 3'UTR editing but relied on three microRNAs acting on ARPIN. As a result, we found that the migration and invasion of cancer cells were profoundly increased by ADAR1 depletion, and this cellular phenotype was reversed by the exogenous ARPIN expression. Altogether, our data suggest that ADAR1 suppresses breast cancer cell mobility via the upregulation of ARPIN.
Topics: 3' Untranslated Regions; Adenosine Deaminase; MicroRNAs; Neoplasms; RNA Editing; RNA-Binding Proteins; Humans; Cell Line, Tumor; Carrier Proteins
PubMed: 36921992
DOI: 10.14348/molcells.2023.2174 -
International Journal of Molecular... May 2022Adenosine-to-inosine RNA editing is a system of post-transcriptional modification widely distributed in metazoans which is catalyzed by ADAR enzymes and occurs mostly in... (Review)
Review
Adenosine-to-inosine RNA editing is a system of post-transcriptional modification widely distributed in metazoans which is catalyzed by ADAR enzymes and occurs mostly in double-stranded RNA (dsRNA) before splicing. This type of RNA editing changes the genetic code, as inosine generally pairs with cytosine in contrast to adenosine, and this expectably modulates RNA splicing. We review the interconnections between RNA editing and splicing in the context of human cancer. The editing of transcripts may have various effects on splicing, and resultant alternatively spliced isoforms may be either tumor-suppressive or oncogenic. Dysregulated RNA splicing in cancer often causes the release of excess amounts of dsRNA into cytosol, where specific dsRNA sensors provoke antiviral-like responses, including type I interferon signaling. These responses may arrest cell division, causing apoptosis and, externally, stimulate antitumor immunity. Thus, small-molecule spliceosome inhibitors have been shown to facilitate the antiviral-like signaling and are considered to be potential cancer therapies. In turn, a cytoplasmic isoform of ADAR can deaminate dsRNA in cytosol, thereby decreasing its levels and diminishing antitumor innate immunity. We propose that complete or partial inhibition of ADAR may enhance the proapoptotic and cytotoxic effects of splicing inhibitors and that it may be considered a promising addition to cancer therapies targeting RNA splicing.
Topics: Adenosine; Adenosine Deaminase; Antiviral Agents; Humans; Inosine; Neoplasms; RNA Splicing; RNA, Double-Stranded; RNA-Binding Proteins
PubMed: 35563631
DOI: 10.3390/ijms23095240 -
The Biochemical Journal May 1981Adenosine deaminase was purified 3038-fold to apparent homogeneity from human leukaemic granulocytes by adenosine affinity chromatography. The purified enzyme has a...
Adenosine deaminase was purified 3038-fold to apparent homogeneity from human leukaemic granulocytes by adenosine affinity chromatography. The purified enzyme has a specific activity of 486 mumol/min per mg of protein at 35 degrees C. It exhibits a single band when subjected to sodium dodecyl sulphate/polyacrylamide-gel electrophoresis, non-denaturing polyacrylamide-gel electrophoresis and isoelectric focusing. The pI is 4.4. The enzyme is a monomeric protein of molecular weight 44000. Both electrophoretic behaviour and molecular weight differ from those of the low-molecular-weight adenosine deaminase purified from human erythrocytes. Its amino acid composition is reported. Tests with periodic acid-Schiff reagent for associated carbohydrate are negative. Of the large group of physiological compounds tested as potential effectors, none has a significant effect. The enzyme is specific for adenosine and deoxyadenosine, with Km values of 48 microM and 34 microM respectively. There are no significant differences in enzyme function on the two substrates. erythro-9-(2-Hydroxy non-3-yl) adenine is a competitive inhibitor, with Ki 15 nM. Deoxycoformycin inhibits deamination of both adenosine and deoxyadenosine, with an apparent Ki of 60-90 pM. A specific antibody was developed against the purified enzyme, and a sensitive radioimmunoassay for adenosine deaminase protein is described.
Topics: Adenosine Deaminase; Adenosine Deaminase Inhibitors; Amino Acids; Chromatography, Affinity; Granulocytes; Humans; Kinetics; Leukemia, Myeloid; Molecular Weight; Nucleoside Deaminases; Radioimmunoassay
PubMed: 6947796
DOI: 10.1042/bj1950389 -
Genes Jul 2021RNA-editing by adenosine deaminases acting on RNA (ADARs) converts adenosines to inosines in structured RNAs. Inosines are read as guanosines by most cellular... (Review)
Review
RNA-editing by adenosine deaminases acting on RNA (ADARs) converts adenosines to inosines in structured RNAs. Inosines are read as guanosines by most cellular machineries. A to I editing has two major functions: first, marking endogenous RNAs as "self", therefore helping the innate immune system to distinguish repeat- and endogenous retrovirus-derived RNAs from invading pathogenic RNAs; and second, recoding the information of the coding RNAs, leading to the translation of proteins that differ from their genomically encoded versions. It is obvious that these two important biological functions of ADARs will differ during development, in different tissues, upon altered physiological conditions or after exposure to pathogens. Indeed, different levels of ADAR-mediated editing have been observed in different tissues, as a response to altered physiology or upon pathogen exposure. In this review, we describe the dynamics of A to I editing and summarize the known and likely mechanisms that will lead to global but also substrate-specific regulation of A to I editing.
Topics: Adenosine; Adenosine Deaminase; Deamination; Humans; Inosine; RNA; RNA Editing; RNA-Binding Proteins
PubMed: 34356042
DOI: 10.3390/genes12071026 -
Journal of Dairy Science Mar 2022The objective of this study was to evaluate ruminal microbiome changes associated with feeding Lactobacillus plantarum GB-LP1 as direct-fed microbials (DFM) in...
The objective of this study was to evaluate ruminal microbiome changes associated with feeding Lactobacillus plantarum GB-LP1 as direct-fed microbials (DFM) in high-producing dairy cow diets. A dual-flow continuous culture system was used in a replicated 4 × 4 Latin square design. A basal diet was formulated to meet the requirements of a cow producing 45 kg of milk per day (16% crude protein and 28% starch). There were 4 experimental treatments: the basal diet without any DFM (CTRL); a mixture of Lactobacillus acidophilus, 1 × 10 cfu/g, and Propionibacterium freudenreichii, 2 × 10 cfu/g [MLP = 0.01% of diet dry matter (DM)]; and 2 different levels of L. plantarum, 1.35 × 10 cfu/g (L1 = 0.05% and L2 = 0.10% of diet DM). Bacterial samples were collected from the fluid and particulate effluents before feeding and at 2, 4, 6, and 8 h after feeding; a composite of all time points was made for each fermentor within their respective fractionations. Bacterial community composition was analyzed through sequencing the V4 region of the 16S rRNA gene using the Illumina MiSeq platform. Sequenced data were analyzed on DADA2, and statistical analyses were performed in R (RStudio 3.0.1, https://www.r-project.org/) and SAS 9.4 (SAS Institute Inc.); orthogonal contrasts were used to compare treatments. Different than in other fermentation scenarios (e.g., silage or beef cattle high-grain diets), treatments did not affect pH or lactic acid concentration. Effects were mainly from overall DFM inclusion, and they were mostly observed in the fluid phase. The relative abundance of the phylum Firmicutes, family Lachnospiraceae, and 6 genera decreased with DFM inclusion, with emphasis on Butyrivibrio_2, Saccharofermentans, and Ruminococcus_1 that are fibrolytic and may display peptidase activity during fermentation. Lachnospiraceae_AC2044_group and Lachnospiraceae_XPB1014_group also decreased in the fluid phase, and their relative abundances were positively correlated with NH-N daily outflow from the fermentors. Specific effects of MLP and L. plantarum were mostly in specific bacteria associated with proteolytic and fibrolytic functions in the rumen. These findings help to explain why, in the previous results from this study, DFM inclusion decreased NH-N concentration without altering pH and lactic acid concentration.
Topics: Adenosine Deaminase; Animal Feed; Animals; Cattle; Diet; Digestion; Female; Fermentation; Intercellular Signaling Peptides and Proteins; Lactation; Lactic Acid; Lactobacillales; Microbiota; Milk; RNA, Ribosomal, 16S; Rumen
PubMed: 34998552
DOI: 10.3168/jds.2021-21025 -
The Journal of Biological Chemistry Jul 1978In many human tissues adenosine deaminase exists as a complex composed of two proteins; one protein has adenosine deaminase activity while the other represents a binding...
In many human tissues adenosine deaminase exists as a complex composed of two proteins; one protein has adenosine deaminase activity while the other represents a binding protein with no other known binding activity. A rapid, quantitative assay for human adenosine deaminase binding protein has been developed utilizing 125I-labeled calf adenosine deaminase. In addition this binding protein has been purified 1,690-fold from human kidney using adenosine deaminase affinity chromatography and appears to be homogenous by sedimentation equilibrium, sodium dodecyl sulfate, and native polyacrylamide gel electrophoresis. This highly purified binding protein exists as a dimer of native molecular weight 190,000, complexes with calf adenosine deaminase in a ratio of 1:2, respectively, and contains carbohydrate which reacts specifically with phytohemagglutinin and ricin lectins. A second form of this adenosine deaminase binding protein may exist, resulting from degradation of its carbohydrate moiety.
Topics: Adenosine Deaminase; Carrier Proteins; Chromatography, Affinity; Chromatography, DEAE-Cellulose; Electrophoresis, Polyacrylamide Gel; Humans; Kidney; Nucleoside Deaminases
PubMed: 659438
DOI: No ID Found -
RNA (New York, N.Y.) Sep 2023The RNA editing enzyme adenosine deaminase acting on RNA 1 (ADAR1) is an essential regulator of the innate immune response to both cellular and viral double-stranded RNA...
The RNA editing enzyme adenosine deaminase acting on RNA 1 (ADAR1) is an essential regulator of the innate immune response to both cellular and viral double-stranded RNA (dsRNA). Adenosine-to-inosine (A-to-I) editing by ADAR1 modifies the sequence and structure of endogenous dsRNA and masks it from the cytoplasmic dsRNA sensor melanoma differentiation-associated protein 5 (MDA5), preventing innate immune activation. Loss-of-function mutations in are associated with rare autoinflammatory disorders including Aicardi-Goutières syndrome (AGS), defined by a constitutive systemic up-regulation of type I interferon (IFN). The murine gene encodes two protein isoforms with distinct functions: ADAR1p110 is constitutively expressed and localizes to the nucleus, whereas ADAR1p150 is primarily cytoplasmic and is inducible by IFN. Recent studies have demonstrated the critical requirement for ADAR1p150 to suppress innate immune activation by self dsRNAs. However, detailed in vivo characterization of the role of ADAR1p150 during development and in adult mice is lacking. We identified a new ADAR1p150-specific knockout mouse mutant based on a single nucleotide deletion that resulted in the loss of the ADAR1p150 protein without affecting ADAR1p110 expression. The died embryonically at E11.5-E12.5 accompanied by cell death in the fetal liver and an activated IFN response. Somatic loss of ADAR1p150 in adults was lethal and caused rapid hematopoietic failure, demonstrating an ongoing requirement for ADAR1p150 in vivo. The generation and characterization of this mouse model demonstrates the essential role of ADAR1p150 in vivo and provides a new tool for dissecting the functional differences between ADAR1 isoforms and their physiological contributions.
Topics: Mice; Animals; RNA, Double-Stranded; Mice, Knockout; Adenosine Deaminase; Homeostasis; Protein Isoforms; Embryonic Development
PubMed: 37290963
DOI: 10.1261/rna.079509.122 -
Clinical and Experimental Immunology May 2020The absence of adenosine deaminase (ADA) causes severe combined immune deficiency (SCID), which has been treated with PEGylated bovine-extracted ADA (ADAGEN). ADAGEN was... (Comparative Study)
Comparative Study
The absence of adenosine deaminase (ADA) causes severe combined immune deficiency (SCID), which has been treated with PEGylated bovine-extracted ADA (ADAGEN). ADAGEN was recently replaced by a PEGylated recombinant bovine ADA, expressed in Escherichia coli (elapegademase, ELA-ADA). Limited information on ELA-ADA is available. ADA enzymatic activity of ELA-ADA and ADAGEN was assessed in vitro at diverse dilutions. ADA activity and immune reconstitution in an ADA-SCID patient treated with ELA-ADA were compared with age-matched patients previously treated with ADAGEN. ADA activity and thymus reconstitution were evaluated in ADA-deficient mice following ELA-ADA or ADAGEN administered from 7 days postpartum. In vitro, ADA activity of ELA-ADA and ADAGEN were similar at all dilutions. In an ADA-SCID patient, ELA-ADA treatment led to a marked increase in trough plasma ADA activity, which was 20% higher than in a patient previously treated with ADAGEN. A marked increase in T cell numbers and generation of naive T cells was evident following 3 months of ELA-ADA treatment, while T cell numbers increased following 4 months in 3 patients previously treated with ADAGEN. T cell proliferations stimulation normalized and thymus shadow became evident following ELA-ADA treatment. ADA activity was significantly increased in the blood of ADA-deficient mice following ELA-ADA compared to ADAGEN, while both treatments improved the mice weights, the weight, number of cells in their thymus and thymocyte subpopulations. ELA-ADA has similar in- vitro and possibly better in-vivo activity than ADAGEN. Future studies will determine whether ELA-ADA results in improved long-term immune reconstitution.
Topics: Adenosine Deaminase; Agammaglobulinemia; Animals; Humans; Mice; Mice, Knockout; Severe Combined Immunodeficiency; T-Lymphocytes; Thymus Gland
PubMed: 31989577
DOI: 10.1111/cei.13420 -
Molecular and Cellular Biology Sep 1984The structure of human adenosine deaminase mRNA from normal and mutant lymphoblasts was examined by sequence analysis of a cDNA for normal mRNA and electrophoretic... (Comparative Study)
Comparative Study
The structure of human adenosine deaminase mRNA from normal and mutant lymphoblasts was examined by sequence analysis of a cDNA for normal mRNA and electrophoretic analyses of DNA fragments generated by S1 endonuclease cleavage of mRNA-cDNA hybrids. The 1,533-base sequence of the cloned cDNA represents the complete mRNA sequence with the possible exception of some of the 5' untranslated region. S1 nuclease analyses of hybrids between cloned cDNA and normal adenosine deaminase mRNA confirmed that a 76-base sequence in a previously examined adenosine deaminase cDNA is an intron. S1 nuclease analyses of mRNAs from seven mutant cell lines demonstrated that four of the mutants, those in the GM-2471, GM-2756, GM-4258, and GM-2606 cells, contain small defects, such as single-base changes, that are not detectable by the S1 nuclease technique. Three of the mRNAs, those in GM-3043, GM-2294, and GM-2825A cells, do contain defects detectable with S1 nuclease. These defects differ from each other and have been mapped to specific regions of the mRNA. Some or all of these defective mRNAs are postulated to result from anomalous RNA processing.
Topics: Adenosine Deaminase; Amino Acid Sequence; Base Sequence; Cell Line; DNA; Endonucleases; Humans; Mutation; Nucleic Acid Hybridization; Nucleoside Deaminases; Poly A; RNA; RNA, Messenger; Single-Strand Specific DNA and RNA Endonucleases
PubMed: 6208479
DOI: 10.1128/mcb.4.9.1712-1717.1984 -
Zoological Research Nov 2022The evolutionary and functional features of RNA editing are well studied in mammals, cephalopods, and insects, but not in birds. Here, we integrated transcriptomic and...
The evolutionary and functional features of RNA editing are well studied in mammals, cephalopods, and insects, but not in birds. Here, we integrated transcriptomic and whole-genomic analyses to exhaustively characterize the expansive repertoire of adenosine-to-inosine (A-to-I) RNA editing sites (RESs) in the chicken. In addition, we investigated the evolutionary status of the chicken editome as a potential mechanism of domestication. We detected the lowest editing level in the liver of chickens, compared to muscles in humans, and found higher editing activity and specificity in the brain than in non-neural tissues, consistent with the brain's functional complexity. To a certain extent, specific editing activity may account for the specific functions of tissues. Our results also revealed that sequences critical to RES secondary structures remained conserved within avian evolution. Furthermore, the RNA editome was shaped by purifying selection during chicken domestication and most RESs may have served as a selection pool for a few functional RESs involved in chicken domestication, including evolution of nervous and immune systems. Regulation of RNA editing in chickens by adenosine deaminase acting on RNA (ADAR) enzymes may be affected by non-ADAR factors whose expression levels changed widely after knockdown. Collectively, we provide comprehensive lists of candidate RESs and non-ADAR-editing regulators in the chicken, thus contributing to our current understanding of the functions and evolution of RNA editing in animals.
Topics: Animals; Humans; Adenosine; Adenosine Deaminase; Chickens; Genomics; Inosine; RNA; RNA Editing; Transcriptome
PubMed: 36266925
DOI: 10.24272/j.issn.2095-8137.2022.331