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PubMed1999

Regulation of insulin-like growth factor I receptor promoter activity by wild-type and mutant versions of the WT1 tumor suppressor.

The insulin-like growth factor I (IGF-I) receptor is a transmembrane tyrosine kinase that mediates the growth-promoting effects of IGF-I and IGF-II. Changes in IGF-I receptor messenger RNA levels are reflected in cell surface receptor number, and modulation of IGF-I receptor levels affects tumorigenicity in numerous cellular models; thus, control of IGF-I receptor gene expression appears to be an important level at which cellular proliferation and tumorigenic potential may be regulated. We have previously shown that the product of the WT1 Wilms' tumor suppressor gene represses IGF-I receptor gene expression both in vitro and in vivo, and that decreased WT1 levels are correlated with up-regulation of IGF-I receptor gene expression in Wilms' tumor, benign prostatic hyperplasia, and breast cancer. Gene regulation by WT1 is complex, in that the WT1 gene encodes a variety of products as a result of alternative splicing and RNA editing, and a number of missense point mutations have been characterized in Wilms' tumor-associated syndromes. Additionally, the WT1 protein has been demonstrated to self-associate through its N-terminal domain, although the role of this intermolecular interaction in transcriptional regulation by WT1 is unclear. In this report, we analyze the relative activity of wild-type and mutant versions of the WT1 protein with respect to IGF-I receptor promoter activity in transient transfection assays and assess the potential contribution of WT1 self-association to IGF-I receptor regulation using the yeast two-hybrid system. Of the naturally occurring variations in WT1 structure, only the presence of a three-amino acid KTS insert in the zinc finger domain introduced by alternative splicing of exon 9 had a significant effect on WT1 repression of IGF-I receptor promoter activity. The N- and C-terminal domains of WT1 also exhibited partial repression, as did the most common mutant version of the WT1 protein associated with Denys-Drash syndrome. Mutations in the WT1 N-terminus attenuated WT1 self-association in the yeast two-hybrid system, but did not impair transcriptional repression. Our results suggest that 1) the DNA-binding capacity of WT1 is critical for maximal repression of the IGF-I receptor promoter, but some effects may be mediated through protein-protein interactions involving the N-terminal domain; 2) WT1 self-association may not be required for repression of the IGF-I receptor promoter; and 3) the Denys-Drash syndrome version of the WT1 protein may exhibit residual or possible gain of function activity in some contexts rather than exerting dominant negative effects, as has been proposed previously.

Animals↗

PubMed2003

Intestinal lipoprotein assembly in apobec-1-/- mice reveals subtle alterations in triglyceride secretion coupled with a shift to larger lipoproteins.

Mammalian enterocytes express apolipoprotein (apo)B-48, which is produced after posttranscriptional RNA editing of the nuclear apoB-100 transcript by the catalytic deaminase apobec-1. Earlier studies in apobec-1-/- mice revealed an apoB-100-only lipoprotein profile but no gross defects in triglyceride absorption. However, subtle defects may have been obscured by the mixed genetic background. In addition, the intrinsic susceptibility to proteolytic degradation of intestinal apoB-100 and apoB-48 has been questioned. Accordingly, we examined triglyceride absorption, intestinal apoB expression, and lipoprotein secretion in apobec-1-/- mice backcrossed into a C57BL/6 background. Inbred apobec-1-/- mice absorb triglyceride normally, yet secrete triglyceride-rich lipoproteins more slowly than wild-type congenic controls. There was comparable induction of apoB synthesis in response to fat feeding in both genotypes, but apoB-100 was preferentially retained and more extensively degraded than apoB-48. By contrast, synthesis, secretion, and content of apo A-IV were indistinguishable in apobec-1-/- and wild-type mice with 100% recovery, suggesting no degradation of this apoprotein in either genotype. Newly secreted lipoproteins from isolated enterocytes of wild-type mice revealed apoB-48 in both high-density lipoproteins and very low-density lipoproteins. By contrast, apobec-1-/- mice secreted apoB-100-containing particles that were almost exclusively in the low and very low-density lipoproteins range with no apoB-100-containing high-density lipoproteins. These studies establish the existence of preferential degradation of intestinal apoB-100 and subtle defects in triglyceride secretion in apobec-1-/- mice, coupled with a shift to the production of larger particles, findings that suggest an important divergence in intestinal lipoprotein assembly pathways with the different isoforms of apoB.

APOBEC-1 Deaminase↗

PubMed1997

Control of rat GluR6 glutamate receptor open probability by protein kinase A and calcineurin.

1. We have used non-stationary variance analysis to examine the single channel conductance and the probability of channel opening at the peak of the homomeric GluR6 response (Po,peak) to 100-200 ms application (10-90% exchange time, 0.3 ms) of glutamate onto excised membrane patches from transiently transfected human embryonic kidney cells (HEK 293). 2. Our determinations of both Po,peak and single channel conductance of simulated current responses are insensitive to system filtering, response rise time, desensitization rate and measured variation in our drug perfusion speed. Isolation of stochastic current fluctuations using the local mean response waveform minimizes problems associated with modest rundown of response amplitude during the experiment. 3. The slope conductance calculated from the weighted mean unitary currents for the channels activated in response to glutamate application is 16 pS. Chord conductance between-40 and -80 mV is independent of agonist concentration. Conversion of the codon for glutamine621 to arginine (Q621R) by RNA editing reduces conductance by more than 35-fold to less than 0.4 pS without changing response time course, desensitization, or Po,peak. 4. Po,peak is high at saturating glutamate concentrations (0.65 +/- 0.23; mean +/- S.D.) and varies with agonist concentrations. The half-maximally effective glutamate concentration (EC50) determined for Po,peak (0.2 mM; Hill slope = 0.6) is similar to that determined for the macroscopic peak current amplitude (0.5 mM; Hill slope = 1.0) in response to rapid agonist application. 5. Inclusion of the purified catalytic subunit of cAMP-dependent protein kinase A (PKA) in the patch pipette increases Po,peak to 0.85 +/- 0.12 and co-transfection of cells with a cDNA encoding the catalytic subunit of PKA (C alpha-PKA) increases Po,peak to 0.94 +/- 0.09. 6. Inclusion of purified calcineurin plus its coactivators 200 nM Ca2+ and calmodulin in the patch pipette decreases Po,peak to 0.48 +/- 0.10. The calcineurin-stimulated decrease of Po,peak in cells co-transfected with C alpha-PKA is blocked by 800 nM deltamethrin, a calcineurin inhibitor. Calmodulin, 200 nM Ca2+ and deltamethrin have no effect on Po,peak in the absence of calcineurin. As predicted from its effects on Po,peak, inclusion of calcineurin in the patch pipette accelerates the run-down of whole cell GluR6 responses in cells co-transfected with C alpha-PKA. 7. The effects of both calcineurin and PKA on Po,peak for GluR6 receptors in excised patches occur without any detectable changes to response time course, desensitization, or chord conductance. 8. We conclude that the binding of glutamate to homomeric GluR6 receptors is associated with a high probability of channel opening, which is under the control of two signalling systems that are known to be co-localized at the neuronal membrane: PKA (Po,peak near 1.0) and calcineurin (Po,peak near 0.5).

Animals↗

PubMed1995

Identification by UV cross-linking of oligo(U)-binding proteins in mitochondria of the insect trypanosomatid Crithidia fasciculata.

RNA editing in trypanosomes is the process of insertion and deletion of U residues at specific sites of mitochondrial transcripts mediated by short guide RNAs (gRNAs) that have a 3' oligo(U) extension. Here we describe the identification by UV cross-linking of proteins present in mitochondrial extracts from Crithidia fasciculata with a high affinity for gRNAs, and the characterization of the binding specificity. A 65-kDa protein binds to gRNAs provided they are equipped with a U tail, to post-transcriptionally labelled mitoribosomal 9S and 12S RNAs that also possess a 3' terminal stretch of U residues, and to free oligo(U) sequences with a minimal length of 23-29 nucleotides. It does not bind to a number of control RNAs, one of which has an internal U stretch of 13 residues. Poly(U), but not poly(C) or total yeast RNA, efficiently competes for binding to gRNA. Proteins of 88 kDa and 30 kDa also bind to gRNAs with a U tail, to mitochondrial ribosomal RNAs and to oligo(U). These proteins, however, require longer oligo(U) for binding (> 39 nucleotides) and they also have an affinity for other U-rich RNAs and poly(C). For comparison, part of the analysis was also carried out with a mitochondrial extract from Trypanosoma brucei. In this organism, gRNA-binding proteins of 83 kDa and 64 kDa were found with the same preference for 3'-terminal oligomeric U stretches as the C. fasciculata 65-kDa protein, whereas the binding specificity of a 26-kDa protein resembled that of the C. fasciculata 88-kDa and 30-kDa proteins. The possible involvement of the proteins in the editing process is discussed.

Animals↗

PubMed2006

UTP-bound and Apo structures of a minimal RNA uridylyltransferase.

3'-Uridylylation of RNA is emerging as a phylogenetically widespread phenomenon involved in processing events as diverse as uridine insertion/deletion RNA editing in mitochondria of trypanosomes and small nuclear RNA (snRNA) maturation in humans. This reaction is catalyzed by terminal uridylyltransferases (TUTases), which are template-independent RNA nucleotidyltransferases that specifically recognize UTP and belong to a large enzyme superfamily typified by DNA polymerase beta. Multiple TUTases, recently identified in trypanosomes, as well as a U6 snRNA-specific TUTase enzyme in humans, are highly divergent at the protein sequence level. However, they all possess conserved catalytic and UTP recognition domains, often accompanied by various auxiliary modules present at the termini or between conserved domains. Here we report identification, structural and biochemical analyses of a novel trypanosomal TUTase, TbTUT4, which represents a minimal catalytically active RNA uridylyltransferase. The TbTUT4 consists of only two domains that define the catalytic center at the bottom of the nucleoside triphosphate and RNA substrate binding cleft. The 2.0 Angstroms crystal structure reveals two significantly different conformations of this TUTase: one molecule is in a relatively open apo conformation, whereas the other displays a more compact TUTase-UTP complex. A single nucleoside triphosphate is bound in the active site by a complex network of interactions between amino acid residues, a magnesium ion and highly ordered water molecules with the UTP's base, ribose and phosphate moieties. The structure-guided mutagenesis and cross-linking studies define the amino acids essential for catalysis, uracil base recognition, ribose binding and phosphate coordination by uridylyltransferases. In addition, the cluster of positively charged residues involved in RNA binding is identified. We also report a 2.4 Angstroms crystal structure of TbTUT4 with the bound 2' deoxyribonucleoside, which provides the structural basis of the enzyme's preference toward ribonucleotides.

Amino Acid Sequence↗

PubMed2004

How an RNA ligase discriminates RNA versus DNA damage.

T4 RNA ligase 2 (Rnl2) exemplifies a family of RNA-joining enzymes that includes protozoan RNA-editing ligases. Rnl2 efficiently seals 3'-OH/5'-PO4 RNA nicks in either a duplex RNA or an RNA:DNA hybrid but cannot seal DNA nicks. RNA specificity arises from a requirement for at least two ribonucleotides immediately flanking the 3'-OH of the nick; the rest of the nicked duplex can be replaced by DNA. The terminal 2'-OH at the nick is important for the attack of the 3'-OH on the 5'-adenylated strand to form a phosphodiester, but dispensable for nick recognition and adenylylation of the 5'-PO4 strand. The penultimate 2'-OH is important for nick recognition. Stable binding of Rnl2 at a nick depends on contacts to both the N-terminal adenylyltransferase domain and its signature C-terminal domain. Nick sensing also requires adenylylation of Rnl2. These results provide insights to the evolution of nucleic acid repair systems.

Bacteriophage T4↗

PubMed2005

Heterochromatin: on the ADAR radar?

Vigilin proteins, the absence of which is known to cause abnormalities in heterochromatin, have been found to bind edited RNAs. Molecular complexes including vigilin comprise proteins involved with RNA editing and with DNA repair, making connections between these processes and RNA-based silencing mechanisms.

Autoantigens↗

PubMed1995

RNA-d2: a computer program for editing and display of RNA secondary structures.

RNA-d2 is a user-friendly program developed for interactively generating aesthetic and non-overlapping drawings of RNA secondary structures. It designed so that the drawings can be edited in a very natural and intuitive way, in order to emphasize structural homologies between several molecules, as well as the foldings themselves to update the base-pair sets according to new data. The program automatically produces a polygonal display in which the unpaired nucleotides are regularly positioned on circles and the stems harmoniously distributed on their periphery. RNA secondary structures can be encoded via the keyboard, but the program also automatically draws output files from thermodynamic prediction programs. The user interacts directly on different screen displays according to the editing functions. Rotation/translation of any subdomain and deletion of stems are performed on a coloured backbone view to make easier the identification of structural features, whereas addition of new base-pairings and numbering manipulation are realized on a complete polygonal view. Each modification is displayed in real time on the screen. When the display is obscured by numerous overlaps despite the colour code of the backbone view, an automatic function progressively straightens the subdomains which are highly compacted by very dissymmetric internal loops. RNA-d2 allows easy untangling and editing of RNA molecules > 1000 nucleotides long.

Algorithms↗

PubMed1998

Localization of hepatitis delta virus RNA in the nucleus of human cells.

Hepatitis delta virus (HDV) is a human pathogen that can greatly increase the severity of liver damage caused by an hepatitis B infection. HDV contains a circular, single-stranded RNA genome that encodes a unique protein, the delta antigen. Two forms of the delta antigen, deltaAg-S and deltaAg-L, are derived from a single open reading frame by RNA editing. Here we analyze the subcellular distribution of HDV RNA and its spatial relationship to known intranuclear structures. The human hepatoma cell line Huh7 was stably transfected with wild-type HDV cDNA and the viral RNAs were localized by in situ hybridization and fluorescence confocal microscopy. HDV RNA is detected throughout the nucleoplasm, with additional concentration in focal structures closely associated with nuclear speckles or clusters of interchromatin granules. Both the smaller form of the delta antigen (deltaAg-S), which is required for HDV genomic replication, and the larger form of the delta antigen (deltaAg-L), which represses replication, co-localize with delta RNA throughout the nucleoplasm and in the foci. However, the foci do not incorporate bromo-UTP and do not concentrate either RNA polymerase II or cleavage and polyadenylation factors required for viral RNA synthesis and 3' end processing, respectively. Thus, it is unlikely that the delta foci represent major sites of viral transcription or replication. In conclusion, the data show that viral RNA-protein complexes accumulate in structures closely associated with interchromatin granules, a subnuclear domain highly enriched in small nuclear ribonucleoproteins, poly(A+) RNA, and RNA splicing protein factors. This implies a specific compartmentalization of ribonucleoproteins in the nucleus.

Carcinoma, Hepatocellular↗

PubMed1997

The guide RNA database.

The RNA editing process in protozoan parasites is controlled by small RNA molecules known as guide RNAs (gRNAs). The gRNA database is a comprehensive compilation of published guide RNA sequences from eight different kinetoplastid organisms. In addition to the RNA primary sequences, information on the gene localization, the experimental verification of the transcripts, and literature citations are provided. Accessory information includes the secondary structures of fourTrypanosoma bruceigRNAs as well as a computer modelled three dimensional gRNA structure. The database is made available as a hypertext document accessible via the World Wide Web (WWW) or from the authors in a printed form.

Animals↗

PubMed1994

Cryopreservation of Plant Mitochondria as a Tool for Protein Import or in Organello Protein Synthesis Studies.

Cryopreserved chloroplasts and thylakoids have recently been proven to be suitable for protein import and integration assays. The possibility of recovering intact plant mitochondria after storage would also facilitate a wide range of investigations that are currently underway on the molecular biology of these organelles, e.g. mitochondrial transcription, RNA editing, in organello protein synthesis, and protein or transfer RNA import. Therefore, we addressed the question whether cryopreservation of isolated plant mitochondria was also possible. Tobacco (Nicotiana tabacum) or broad bean (Vicia faba) mitochondria were quick frozen and stored in liquid nitrogen in the presence of various concentrations of ethylene glycol as a cryoprotectant. After thawing, up to 90% of the mitochondria stored in 5 to 10% ethylene glycol appeared to retain an intact outer membrane and normal oxidative phosphorylation activity. Their ultrastructural aspect, observed by electron microscopy, was similar to that of freshly prepared mitochondria. Furthermore, efficient in organello protein synthesis was carried out with mitochondria stored in the presence of 7.5% ethylene glycol. Finally, the precursor of the [beta] subunit of the mitochondrial F1-ATPase from Nicotiana plumbaginifolia was successfully translocated into V. faba cryopreserved mitochondria and processed. These data demonstrate that plant mitochondria cryopreserved under the conditions described here remain functional and can be used for a variety of physiological and biochemical studies.

Journal Article↗

PubMed1995

Are 5S ribosomal RNA primary transcripts edited?

Comparative analysis of the nucleotide sequences of plant 5S rRNA genes shows numerous discrepancies with the mature 5S rRNAs. Detailed inspection of these differences revealed that they are mainly due to single nucleotide substitutions, insertions and deletions. In several cases also longer insertions were found, two of which are particularly interesting. Their location in loops resembles tRNA introns. One of these insertions is 79 nucleotides long and can potentially form a tRNA-like structure, with 50% homology to plant tRNAGly. This observation led us to propose that, in the maturation of some 5S rDNA transcripts, editing and splicing mechanisms may be involved.

Base Sequence↗

PubMed2003

In vitro deamination of cytosine to uracil in single-stranded DNA by apolipoprotein B editing complex catalytic subunit 1 (APOBEC1).

Apolipoprotein B-editing complex catalytic subunit 1 (APOBEC1) is the catalytic component of an RNA-editing complex that deaminates C6666 --> U in apolipoprotein B RNA in gastrointestinal tissue, thereby generating a premature stop codon. Whereas RNA is the physiological substrate of APOBEC1, recent experiments have strongly indicated that, when expressed in bacteria, APOBEC1 and some of its homologues can deaminate cytosine in DNA. Indeed, genetic evidence demonstrates that the physiological function of activation-induced deaminase, a B lymphocyte-specific APOBEC1 homologue, is to perform targeted deamination of cytosine within the immunoglobulin locus, thereby triggering antibody gene diversification. However, biochemical evidence of in vitro DNA deamination by members of the APOBEC family is still needed. Here, we show that deamination of cytosine to uracil in DNA can be achieved in vitro using partially purified APOBEC1 from extracts of transformed Escherichia coli. Thus, APOBEC1 can deaminate cytosine in both RNA and DNA. Strikingly, its activity on DNA is specific for single-stranded DNA and exhibits dependence on local sequence context.

APOBEC-1 Deaminase↗

PubMed1994

Trypanosoma brucei mitochondrial CR4 gene encodes an extensively edited mRNA with completely edited sequence only in bloodstream forms.

Several kinetoplastid mitochondrial genes cannot be expressed without RNA editing of their transcripts to create a functional open reading frame. We have examined one such mitochondrial gene, CR4, in Trypanosoma brucei EATRO164 and find extensive editing of transcripts in both bloodstream and procyclic life cycle stages. However, a consensus edited sequence for the entire mRNA occurs only in the bloodstream stage. The unedited CR4 transcript is 283 nucleotides in length, not including the poly(A) tail. A total of 325 uridines are inserted, and 40 uridines deleted, to create the mature mRNA which encodes a very hydrophobic protein.

Amino Acid Sequence↗

PubMed1994

REPR and complementation factor(s) interact to modulate rat apolipoprotein B mRNA editing in response to alterations in cellular cholesterol flux.

Apolipoprotein B (apoB) mRNA editing is a post-transcriptional cytidine deamination involving several protein factor(s), one of which has recently been cloned. We have examined the effects of alterations in cellular cholesterol flux in the rat liver and small intestine as a means of dissecting the physiologic mechanisms regulating apoB mRNA editing, both in vivo and in isolated S-100 extracts. Hepatic cholesteryl ester accumulation was produced by feeding rats a high cholesterol diet, alone, or in combination with either ethinyl estradiol treatment, or after induction of hypothyroidism. Endogenous hepatic apoB mRNA editing decreased in parallel with the increase in cellular cholesteryl ester content (r = -0.948, P < 0.001). None of these conditions altered endogenous intestinal apoB mRNA editing. Hepatic S-100 extracts demonstrated decreased in vitro apoB RNA editing activity, in parallel with the changes observed in vivo. By contrast, the activity of intestinal S-100 extracts demonstrated a paradoxical increase in hypothyroid rats and a similar, paradoxical decrease in hyperthyroid rats, when compared to controls. Hepatic REPR mRNA, quantitated by RNase protection assay, showed a 25-50% decrease in cholesterol-fed rats. The editing activity of hepatic S-100 extracts prepared from cholesterol-fed, hypothyroid rats was restored to control levels with REPR supplementation but not with chicken intestinal S-100 extracts, suggesting that changes in REPR, but not complementation activity, may play a critical role in the regulation of apoB mRNA editing in rat liver. By contrast, the editing activity of intestinal S-100 extracts prepared from hyperthyroid animals was unaltered by supplementation with REPR, but was restored to control levels after the addition of chicken intestinal S-100 extracts. Taken together, the data suggest that tissue-specific factors regulate apoB mRNA editing in the rat and that the complex interplay of REPR and complementation factor(s) may be modulated in response to alterations in cholesterol flux, in vivo.

APOBEC-1 Deaminase↗

PubMed1993

The differential expression of 16 NMDA and non-NMDA receptor subunits in the rat spinal cord and in periaqueductal gray.

Diverse arrays of glutamate-gated channels in the spinal cord and associated pathways are partly responsible for sensory input, for altered sensitivity to peripheral stimuli during inflammation, and for generation of motor patterns. The expression of 16 genes, encoding all known subunits for the NMDA receptor (NR1, NR2A to NR2D), AMPA/low-affinity kainate (GluR-A to -D), high-affinity kainate ionotropic receptors (KA-1, -2, GluR-5 to -7) and two orphan receptor subunits (delta-1 and -2) was examined by in situ hybridization in rat lumbar spinal cord, and in the periaqueductal gray. Subunit mRNAs for GluR-A, -B Flip, KA-2, and NR1 were abundant in the dorsal horn, with NR2D lightly expressed. Occasional cells in lamina II contained NR2C mRNA. While the GluR-A gene was preferentially expressed in laminae I and II-outer, GluR-B mRNA was evenly expressed throughout all superficial laminae (I, II-outer, II-inner, and III). Large neurons in laminae IV and V expressed mainly NR1, GluR-C, and to lesser extents the GluR-B, GluR-D, and NR2D genes. Lamina I contained occasional cells expressing the GluR-5 gene, whereas GluR-7 mRNA was present in scattered cells in all superficial laminae. In motor neurons, GluR-B Flip, -C Flip, -D Flip, and NR1 mRNAs were expressed heavily, and those of NR2D and KA-1 weakly. Possibly connected to the RNA editing mechanism, GluR-B was the only subunit whose RNA was concentrated in motor neuron cell nuclei in addition to the cytoplasm. delta-1 and -2 mRNAs were found at low levels throughout the gray matter. NR2A, NR2B, and GluR-6 mRNAs were undetectable. For the periaqueductal gray, prominent mRNAs were GluR-A, -B, and NR1. An en passant observation concerned high levels of NR2C mRNA in the pineal gland.

Animals↗

PubMed1998

The protein family of RNA helicases.

RNA helicases represent a large family of proteins that have been detected in almost all biological systems where RNA plays a central role. They are ubiquitously distributed over a wide range of organisms and are involved in nuclear and mitochondrial splicing processes, RNA editing, rRNA processing, translation initiation, nuclear mRNA export, and mRNA degradation. RNA helicases are described as essential factors in cell development and differentiation, and some of them play a role in transcription and replication of viral single-stranded RNA genomes. Comparisons of the conserved sequences reveal a close relationship between them and suggest that these proteins might be derived from a common ancestor. Biochemical studies have revealed a strong dependence of the unwinding activity on ATP hydrolysis. Although RNA helicase activity has only been demonstrated for a few examples yet, it is generally believed that all members of the largest subgroups, the DEAD and DEAH box proteins, exhibit this activity.

Amino Acid Sequence↗

PubMedDate not supplied

Candidate editases for GluR channels in single neurons of rat hippocampus and cerebellum.

RNA editing by site selective adenosine deamination changes codons in several nuclear transcripts in the mammalian brain and affects critical properties of the encoded proteins, as exemplified by the calcium permeability of AMPA receptor channels. The recently cloned RNA dependent adenosine deaminases ADAR1, ADAR2 and ADAR3 form a small family of sequence-related candidate editases which are expressed in brain and other tissues at distinct levels and patterns. We have employed single-cell polymerase chain reaction of hippocampal CA1 and CA3 pyramidal neurons and cerebellar Purkinje and Bergmann glial cells in an attempt to evaluate the expression of these enzymes at a cellular level. We found ADAR2 expressed in all cells analyzed; approximately 50% of the cells co-expressed ADAR1 or ADAR3. The differential ADAR expression revealed by our study might underlie the distinct editing efficiencies and selectivities in different GluR subunit transcripts.

Adenosine Deaminase↗