Global impacts of an extreme solar particle event under different geomagnetic field strengths.

Solar particle events (SPEs) are short-lived bursts of high-energy particles from the solar atmosphere and are widely recognized as posing significant economic risks to modern society. Most SPEs are relatively weak and have minor impacts on the Earth's environment, but historic records contain much stronger SPEs which have the potential to alter atmospheric chemistry, impacting climate and biological life. The impacts of such strong SPEs would be far more severe when the Earth's protective geomagnetic field is weak, such as during past geomagnetic excursions or reversals. Here, we model the impacts of an extreme SPE under different geomagnetic field strengths, focusing on changes in atmospheric chemistry and surface radiation using the atmosphere-ocean-chemistry-climate model SOCOL3-MPIOM and the radiation transfer model LibRadtran. Under current geomagnetic conditions, an extreme SPE would increase NOx concentrations in the polar stratosphere and mesosphere, causing reductions in extratropical stratospheric ozone lasting for about a year. In contrast, with no geomagnetic field, there would be a substantial increase in NOx throughout the entire atmosphere, resulting in severe stratospheric ozone depletion for several years. The resulting ground-level ultraviolet (UV) radiation would remain elevated for up to 6 y, leading to increases in UV index up to 20 to 25% and solar-induced DNA damage rates by 40 to 50%. The potential evolutionary impacts of past extreme SPEs remain an important question, while the risks they pose to human health in modern conditions continue to be underestimated.

The impact of mRNA poly(A) tail length on eukaryotic translation stages.

The poly(A) tail plays an important role in maintaining mRNA stability and influences translation efficiency via binding with PABP. However, the impact of poly(A) tail length on mRNA translation remains incompletely understood. This study explores the effects of poly(A) tail length on human translation. We determined the translation rates in cell lysates using mRNAs with different poly(A) tails. Cap-dependent translation was stimulated by the poly(A) tail, however, it was largely independent of poly(A) tail length, with an exception observed in the case of the 75 nt poly(A) tail. Conversely, cap-independent translation displayed a positive correlation with poly(A) tail length. Examination of translation stages uncovered the dependence of initiation and termination on the presence of the poly(A) tail, but the efficiency of initiation remained unaffected by poly(A) tail extension. Further study unveiled that increased binding of eRFs to the ribosome with the poly(A) tail extension induced more efficient hydrolysis of peptidyl-tRNA. Building upon these findings, we propose a crucial role for the 75 nt poly(A) tail in orchestrating the formation of a double closed-loop mRNA structure within human cells which couples the initiation and termination phases of translation.

Recognition of 3' nucleotide context and stop codon readthrough are determined during mRNA translation elongation.

The nucleotide context surrounding stop codons significantly affects the efficiency of translation termination. In eukaryotes, various 3' contexts that are unfavorable for translation termination have been described; however, the exact molecular mechanism that mediates their effects remains unknown. In this study, we used a reconstituted mammalian translation system to examine the efficiency of stop codons in different contexts, including several previously described weak 3' stop codon contexts. We developed an approach to estimate the level of stop codon readthrough in the absence of eukaryotic release factors (eRFs). In this system, the stop codon is recognized by the suppressor or near-cognate tRNAs. We observed that in the absence of eRFs, readthrough occurs in a 3' nucleotide context-dependent manner, and the main factors determining readthrough efficiency were the type of stop codon and the sequence of the 3' nucleotides. Moreover, the efficiency of translation termination in weak 3' contexts was almost equal to that in the tested standard context. Therefore, the ability of eRFs to recognize stop codons and induce peptide release is not affected by mRNA context. We propose that ribosomes or other participants of the elongation cycle can independently recognize certain contexts and increase the readthrough of stop codons. Thus, the efficiency of translation termination is regulated by the 3' nucleotide context following the stop codon and depends on the concentrations of eRFs and suppressor/near-cognate tRNAs.

eIF3j facilitates loading of release factors into the ribosome.

eIF3j is one of the eukaryotic translation factors originally reported as the labile subunit of the eukaryotic translation initiation factor eIF3. The yeast homolog of this protein, Hcr1, has been implicated in stringent AUG recognition as well as in controlling translation termination and stop codon readthrough. Using a reconstituted mammalian in vitro translation system, we showed that the human protein eIF3j is also important for translation termination. We showed that eIF3j stimulates peptidyl-tRNA hydrolysis induced by a complex of eukaryotic release factors, eRF1-eRF3. Moreover, in combination with the initiation factor eIF3, which also stimulates peptide release, eIF3j activity in translation termination increases. We found that eIF3j interacts with the pre-termination ribosomal complex, and eRF3 destabilises this interaction. In the solution, these proteins bind to each other and to other participants of translation termination, eRF1 and PABP, in the presence of GTP. Using a toe-printing assay, we determined the stage at which eIF3j functions - binding of release factors to the A-site of the ribosome before GTP hydrolysis. Based on these data, we assumed that human eIF3j is involved in the regulation of translation termination by loading release factors into the ribosome.

Polymyxin B Conjugates with Bio-Inspired Synthetic Polymers of Different Nature.

The emergence and growth of bacterial resistance to antibiotics poses an enormous threat to humanity in the future. In this regard, the discovery of new antibiotics and the improvement of existing ones is a priority task. In this study, we proposed the synthesis of new polymeric conjugates of polymyxin B, which is a clinically approved but limited-use peptide antibiotic. In particular, three carboxylate-bearing polymers and one synthetic glycopolymer were selected for conjugation with polymyxin B (PMX B), namely, poly(α,L-glutamic acid) (PGlu), copolymer of L-glutamic acid and L-phenylalanine (P(Glu-co-Phe)), copolymer of N-vinyl succinamic acid and N-vinylsuccinimide (P(VSAA-co-VSI)), and poly(2-deoxy-2-methacrylamido-D-glucose) (PMAG). Unlike PGlu and PMAG, P(Glu-co-Phe) and P(VSAA-co-VSI) are amphiphilic and form nanoparticles in aqueous media. A number of conjugates with different polymyxin B loading were synthesized and characterized. In addition, the complex conjugates of PGLu or PMAG with polymyxin B and deferoxamine (siderophore) were obtained. A release of PMX B from Schiff base and amide-linked polymer conjugates was studied in model buffer media with pH 7.4 and 5.8. In both cases, a more pronounced release was observed under slightly acidic conditions. The cytotoxicity of free polymers and PMX B as well as their conjugates was examined in human embryonic kidney cells (HEK 293T cell line). All conjugates demonstrated reduced cytotoxicity compared to the free antibiotic. Finally, the antimicrobial efficacy of the conjugates against Pseudomonas aeruginosa was determined and compared. The lowest values of minimum inhibitory concentrations (MIC) were observed for polymyxin B and polymyxin B/deferoxamine conjugated with PMAG. Among the polymers tested, PMAG appears to be the most promising carrier for delivery of PMX B in conjugated form due to the good preservation of the antimicrobial properties of PMX B and the ability of controlled drug release.

Cyanocobalamin-Modified Colistin-Hyaluronan Conjugates: Synthesis and Bioactivity.

Polymeric drug delivery systems enhance the biopharmaceutical properties of antibiotics by increasing their bioavailability, providing programmable and controlled-release properties, and reducing toxicity. In addition, drug delivery systems are a promising strategy to improve the intestinal permeability of various antimicrobial agents, including colistin (CT). This study describes the modification of conjugates based on CT and hyaluronic acid (HA) with cyanocobalamin (vitamin B12). Vitamin B12 was chosen as a targeting ligand because it has its own absorption pathway in the small intestine. The resulting polysaccharide conjugates contained 95 µg/mg vitamin B12 and the CT content was 335 µg/mg; they consisted of particles of two sizes, 98 and 702 nm, with a ζ-potential of approximately -25 mV. An in vitro release test at pH 7.4 and pH 5.2 showed an ultra-slow release of colistin of approximately 1% after 10 h. The modified B12 conjugates retained their antimicrobial activity at the level of pure CT (minimum inhibitory concentration was 2 µg/mL). The resulting delivery systems also reduced the nephrotoxicity of CT by 30-40% (HEK 293 cell line). In addition, the modification of B12 improved the intestinal permeability of CT, and the apparent permeability coefficient of HA-CT-B12 conjugates was 3.5 × 10-6 cm/s, corresponding to an in vivo intestinal absorption of 50-100%. Thus, vitamin-B12-modified conjugates based on CT and HA may be promising oral delivery systems with improved biopharmaceutical properties.

In-Frame Deletion of Dystrophin Exons 8-50 Results in DMD Phenotype.

Mutations that prevent the production of proteins in the DMD gene cause Duchenne muscular dystrophy. Most frequently, these are deletions leading to reading-frame shift. The "reading-frame rule" states that deletions that preserve ORF result in a milder Becker muscular dystrophy. By removing several exons, new genome editing tools enable reading-frame restoration in DMD with the production of BMD-like dystrophins. However, not every truncated dystrophin with a significant internal loss functions properly. To determine the effectiveness of potential genome editing, each variant should be carefully studied in vitro or in vivo. In this study, we focused on the deletion of exons 8-50 as a potential reading-frame restoration option. Using the CRISPR-Cas9 tool, we created the novel mouse model DMDdel8-50, which has an in-frame deletion in the DMD gene. We compared DMDdel8-50 mice to C57Bl6/CBA background control mice and previously generated DMDdel8-34 KO mice. We discovered that the shortened protein was expressed and correctly localized on the sarcolemma. The truncated protein, on the other hand, was unable to function like a full-length dystrophin and prevent disease progression. On the basis of protein expression, histological examination, and physical assessment of the mice, we concluded that the deletion of exons 8-50 is an exception to the reading-frame rule.

Upconversion Nanoparticles Intercalated in Large Polymer Micelles for Tumor Imaging and Chemo/Photothermal Therapy.

Frontiers in theranostics are driving the demand for multifunctional nanoagents. Upconversion nanoparticle (UCNP)-based systems activated by near-infrared (NIR) light deeply penetrating biotissue are a powerful tool for the simultaneous diagnosis and therapy of cancer. The intercalation into large polymer micelles of poly(maleic anhydride-alt-1-octadecene) provided the creation of biocompatible UCNPs. The intrinsic properties of UCNPs (core@shell structure NaYF4:Yb3+/Tm3+@NaYF4) embedded in micelles delivered NIR-to-NIR visualization, photothermal therapy, and high drug capacity. Further surface modification of micelles with a thermosensitive polymer (poly-N-vinylcaprolactam) exhibiting a conformation transition provided gradual drug (doxorubicin) release. In addition, the decoration of UCNP micelles with Ag nanoparticles (Ag NPs) synthesized in situ by silver ion reduction enhanced the cytotoxicity of micelles at cell growth temperature. Cell viability assessment on Sk-Br-3, MDA-MB-231, and WI-26 cell lines confirmed this effect. The efficiency of the prepared UCNP complex was evaluated in vivo by Sk-Br-3 xenograft regression in mice for 25 days after peritumoral injection and photoactivation of the lesions with NIR light. The designed polymer micelles hold promise as a photoactivated theranostic agent with quattro-functionalities (NIR absorption, photothermal effect, Ag NP cytotoxicity, and Dox loading) that provides imaging along with chemo- and photothermal therapy enhanced with Ag NPs.

Discovery of a novel role of tumor suppressor PDCD4 in stimulation of translation termination.

Programmed cell death 4 protein (PDCD4) regulates many vital cell processes, although is classified as a tumor suppressor because it inhibits neoplastic transformation and tumor growth. For example, PCDC4 has been implicated in the regulation of transcription and mRNA translation. PDCD4 is known to inhibit translation initiation by binding to eukaryotic initiation factor 4A and elongation of oncogenic c- and A-myb mRNAs. Additionally, PDCD4 has been shown to interact with poly(A)-binding protein (PABP), which affects translation termination, although the significance of this interaction is not fully understood. Considering the interaction between PABP and PDCD4, we hypothesized that PDCD4 may also be involved in translation termination. Using in vitro translation systems, we revealed that PDCD4 directly activates translation termination. PDCD4 stimulates peptidyl-tRNA hydrolysis induced by a complex of eukaryotic release factors, eRF1-eRF3. Moreover, in combination with the PABP, which also stimulates peptide release, PDCD4 activity in translation termination increases. PDCD4 regulates translation termination by facilitating the binding of release factors to the ribosome, increasing the GTPase activity of eRF3, and dissociating eRF3 from the posttermination complex. Using a toe-printing assay, we determined the first stage at which PDCD4 functions-binding of release factors to the A-site of the ribosome. However, preventing binding of eRF3 with PABP, PDCD4 suppresses subsequent rounds of translation termination. Based on these data, we assumed that human PDCD4 controls protein synthesis during translation termination. The described mechanism of the activity of PDCD4 in translation termination provides a new insight into its functioning during suppression of protein biosynthesis.

Current advances in gene therapy of mitochondrial diseases.

Mitochondrial diseases (MD) are a heterogeneous group of multisystem disorders involving metabolic errors. MD are characterized by extremely heterogeneous symptoms, ranging from organ-specific to multisystem dysfunction with different clinical courses. Most primary MD are autosomal recessive but maternal inheritance (from mtDNA), autosomal dominant, and X-linked inheritance is also known. Mitochondria are unique energy-generating cellular organelles designed to survive and contain their own unique genetic coding material, a circular mtDNA fragment of approximately 16,000 base pairs. The mitochondrial genetic system incorporates closely interacting bi-genomic factors encoded by the nuclear and mitochondrial genomes. Understanding the dynamics of mitochondrial genetics supporting mitochondrial biogenesis is especially important for the development of strategies for the treatment of rare and difficult-to-diagnose diseases. Gene therapy is one of the methods for correcting mitochondrial disorders.

Nsp1 of SARS-CoV-2 stimulates host translation termination.

Nsp1 of SARS-CoV-2 regulates the translation of host and viral mRNAs in cells. Nsp1 inhibits host translation initiation by occluding the entry channel of the 40S ribosome subunit. The structural study of the Nsp1-ribosomal complexes reported post-termination 80S complex containing Nsp1, eRF1 and ABCE1. Considering the presence of Nsp1 in the post-termination 80S ribosomal complex, we hypothesized that Nsp1 may be involved in translation termination. Using a cell-free translation system and reconstituted in vitro translation system, we show that Nsp1 stimulates peptide release and formation of termination complexes. Detailed analysis of Nsp1 activity during translation termination stages reveals that Nsp1 facilitates stop codon recognition. We demonstrate that Nsp1 stimulation targets eRF1 and does not affect eRF3. Moreover, Nsp1 increases amount of the termination complexes at all three stop codons. The activity of Nsp1 in translation termination is provided by its N-terminal domain and the minimal required part of eRF1 is NM domain. We assume that the biological meaning of Nsp1 activity in translation termination is binding with the 80S ribosomes translating host mRNAs and remove them from the pool of the active ribosomes.

In vitro assay for the efficacy assessment of AAV vectors expressing microdystrophin.

AAV-delivered microdystrophin genes hold great promise for Duchenne muscular dystrophy (DMD) treatment. It is anticipated that the optimization of engineered dystrophin genes will be required to increase the efficacy and reduce the immunogenicity of transgenic proteins. An in vitro system is required for the efficacy testing of genetically engineered dystrophin genes. We report here on the proof of concept for an in vitro assay based on the assessment of sarcolemma damage after repetitively applied electrical stimuli. The primary cell culture of myoblasts was established from wild-type C57BL/10ScSnJ and dystrophin-deficient mdx mice. The preparation parameters and the differentiation of contractile myotubes were optimized. DAPI and TO-PRO-3 dyes were used to assess myotubular membrane permeability in response to electrical pulse stimulation (EPS). Myotubes derived from mdx mice exhibited a greater increase in membrane damage, as assessed by TO-PRO-3-measured permeability after EPS, than was exhibited by the healthy control myotubes. AAV-DJ particles carrying the microdystrophin gene were used to transduce mdx-derived differentiated myotubes. Microdystrophin delivery ameliorated the disease phenotype and reduced the EPS-induced membrane damage to a level comparable to that of the healthy controls. Thus, the in vitro system was shown to be capable of supporting studies on DMD gene therapy.

Method for Rapid Analysis of Mutant RNA Polymerase Activity on Templates Containing Unnatural Nucleotides.

Pairs of unnatural nucleotides are used to expand the genetic code and create artificial DNA or RNA templates. In general, an approach is used to engineer orthogonal systems capable of reading codons comprising artificial nucleotides; however, DNA and RNA polymerases capable of recognizing unnatural nucleotides are required for amplification and transcription of templates. Under favorable conditions, in the presence of modified nucleotide triphosphates, DNA polymerases are able to synthesize unnatural DNA with high efficiency; however, the currently available RNA polymerases reveal high specificity to the natural nucleotides and may not easily recognize the unnatural nucleotides. Due to the absence of simple and rapid methods for testing the activity of mutant RNA polymerases, the development of RNA polymerase recognizing unnatural nucleotides is limited. To fill this gap, we developed a method for rapid analysis of mutant RNA polymerase activity on templates containing unnatural nucleotides. Herein, we optimized a coupled cell-free translation system and tested the ability of three unnatural nucleotides to be transcribed by different T7 RNA polymerase mutants, by demonstrating high sensitivity and simplicity of the developed method. This approach can be applied to various unnatural nucleotides and can be simultaneously scaled up to determine the activity of numerous polymerases on different templates. Due to the simplicity and small amounts of material required, the developed cell-free system provides a highly scalable and versatile tool to study RNA polymerase activity.

Polyadenylate-binding protein-interacting proteins PAIP1 and PAIP2 affect translation termination.

Polyadenylate-binding protein (PABP) stimulates translation termination via interaction of its C-terminal domain with eukaryotic polypeptide chain release factor, eRF3. Additionally, two other proteins, poly(A)-binding protein-interacting proteins 1 and 2 (PAIP1 and PAIP2), bind the same domain of PABP and regulate its translation-related activity. To study the biochemistry of eRF3 and PAIP1/2 competition for PABP binding, we quantified the effects of PAIPs on translation termination in the presence or absence of PABP. Our results demonstrated that both PAIP1 and PAIP2 prevented translation termination at the premature termination codon, by controlling PABP activity. Moreover, PAIP1 and PAIP2 inhibited the activity of free PABP on translation termination in vitro However, after binding the poly(A) tail, PABP became insensitive to suppression by PAIPs and efficiently activated translation termination in the presence of eRF3a. Additionally, we revealed that PAIP1 binds eRF3 in solution, which stabilizes the post-termination complex. These results indicated that PAIP1 and PAIP2 participate in translation termination and are important regulators of readthrough at the premature termination codon.

Fluorescent toeprinting to study the dynamics of ribosomal complexes.

Classical toeprinting is generally used to determine the position of ribosomes on mRNA; however, it has several disadvantages. We describe a fluorescent toeprinting assay that enables easier identification of ribosomal complexes bound to mRNA in vitro. The procedure involves the use of stable and safe fluorescently labeled oligonucleotides for reverse transcription reactions as primers, followed by the analysis of cDNA products using an automatic sequencer. This procedure allows the multiplexing and simultaneous analysis of a large number of samples. Over the past ten years, fluorescent toeprinting was applied to determine the activities of eukaryotic release factors and additional proteins involved in translation termination, to study the dynamics of translation initiation and elongation complexes, and to quantitatively evaluate the observed ribosomal complexes. Because of the simplicity and small amounts of material required, fluorescent toeprinting provides a highly scalable and versatile tool to study ribosomal complexes.

Eukaryotic translation elongation factor 2 (eEF2) catalyzes reverse translocation of the eukaryotic ribosome.

During protein synthesis, a ribosome moves along the mRNA template and, using aminoacyl-tRNAs, decodes the template nucleotide triplets to assemble a protein amino acid sequence. This movement is accompanied by shifting of mRNA-tRNA complexes within the ribosome in a process called translocation. In living cells, this process proceeds in a unidirectional manner, bringing the ribosome to the 3' end of mRNA, and is catalyzed by the GTPase translation elongation factor 2 (EF-G in prokaryotes and eEF2 in eukaryotes). Interestingly, the possibility of spontaneous backward translocation has been shown in vitro for bacterial ribosomes, suggesting a potential reversibility of this reaction. However, this possibility has not yet been tested for eukaryotic ribosomes. Here, using a reconstituted mammalian translation system, we show that the eukaryotic elongation factor eEF2 catalyzes ribosomal reverse translocation at one mRNA triplet. We found that this process requires a cognate tRNA in the ribosomal E-site and cannot occur spontaneously without eEF2. The efficiency of this reaction depended on the concentrations of eEF2 and cognate tRNAs and increased in the presence of nonhydrolyzable GTP analogues. Of note, ADP-ribosylation of eEF2 domain IV blocked reverse translocation, suggesting a crucial role of interactions of this domain with the ribosome for the catalysis of the reaction. In summary, our findings indicate that eEF2 is able to induce ribosomal translocation in forward and backward directions, highlighting the universal mechanism of tRNA-mRNA movements within the ribosome.

Hyaluronan/B12-chitosan polyelectrolyte complex for oral colistin administration.

Polyelectrolyte complexes (PECs) based on polysaccharides, including hyaluronic acid (HA) and chitosan (CS), are promising delivery systems for antimicrobial agents, including oral administration of the peptide antibiotic colistin (CT). Modification of CS with different targeting ligands to improve intestinal permeability is a suitable way to improve the oral bioavailability of polyelectrolyte particles. This study describes the procedure for obtaining CT-containing PECs based on HA and CS modified with cyanocobalamin (vitamin B12). In this case, vitamin B12 is used as a targeting ligand because it is absorbed in the ileum via specific transporter proteins. The resulting PECs had a hydrodynamic size of about 284 nm and a positive ζ-potential of about 26 mV; the encapsulation efficiency was 88.2 % and the CT content was 42.2 µg/mg. The developed systems provided a two-phase drug release: about 50 % of the CT was released in 0.5-1 h, and about 60 % of the antibiotic was cumulatively released in 5 h. The antimicrobial activity of encapsulated CT was maintained at the same level as the pure drug for at least 24 h (minimum inhibitory concentration against Pseudomonas aeruginosa was 2 µg/mL for both). In addition, the apparent permeability coefficient of CT in the PEC formulation was 2.4 × 10-6 cm/s. Thus, the incorporation of CT into HA- and vitamin B12-modified CS-based PECs can be considered as a simple and convenient method to improve the oral delivery of CT.

RNA Interference Effectors Selectively Silence the Pathogenic Variant GNAO1 c.607 G > A In Vitro.

RNA interference (RNAi)-based therapeutics hold the potential for dominant genetic disorders, enabling sequence-specific inhibition of pathogenic gene products. We aimed to direct RNAi for the selective suppression of the heterozygous GNAO1 c.607 G > A variant causing GNAO1 encephalopathy. By screening short interfering RNA (siRNA), we showed that GNAO1 c.607G>A is a druggable target for RNAi. The si1488 candidate achieved at least twofold allelic discrimination and downregulated mutant protein to 35%. We created vectorized RNAi by incorporating the si1488 sequence into the short hairpin RNA (shRNA) in the adeno-associated virus (AAV) vector. The shRNA stem and loop were modified to improve the transcription, processing, and guide strand selection. All tested shRNA constructs demonstrated selectivity toward mutant GNAO1, while tweaking hairpin structure only marginally affected the silencing efficiency. The selectivity of shRNA-mediated silencing was confirmed in the context of AAV vector transduction. To conclude, RNAi effectors ranging from siRNA to AAV-RNAi achieve suppression of the pathogenic GNAO1 c.607G>A and discriminate alleles by the single-nucleotide substitution. For gene therapy development, it is crucial to demonstrate the benefit of these RNAi effectors in patient-specific neurons and animal models of the GNAO1 encephalopathy.

CRISPR/Cas9-generated mouse model with humanizing single-base substitution in the Gnao1 for safety studies of RNA therapeutics.

The development of personalized medicine for genetic diseases requires preclinical testing in the appropriate animal models. GNAO1 encephalopathy is a severe neurodevelopmental disorder caused by heterozygous de novo mutations in the GNAO1 gene. GNAO1 c.607 G>A is one of the most common pathogenic variants, and the mutant protein Gαo-G203R likely adversely affects neuronal signaling. As an innovative approach, sequence-specific RNA-based therapeutics such as antisense oligonucleotides or effectors of RNA interference are potentially applicable for selective suppression of the mutant GNAO1 transcript. While in vitro validation can be performed in patient-derived cells, a humanized mouse model to rule out the safety of RNA therapeutics is currently lacking. In the present work, we employed CRISPR/Cas9 technology to introduce a single-base substitution into exon 6 of the Gnao1 to replace the murine Gly203-coding triplet (GGG) with the codon used in the human gene (GGA). We verified that genome-editing did not interfere with the Gnao1 mRNA or Gαo protein synthesis and did not alter localization of the protein in the brain structures. The analysis of blastocysts revealed the off-target activity of the CRISPR/Cas9 complexes; however, no modifications of the predicted off-target sites were detected in the founder mouse. Histological staining confirmed the absence of abnormal changes in the brain of genome-edited mice. The created mouse model with the "humanized" fragment of the endogenous Gnao1 is suitable to rule out unintended targeting of the wild-type allele by RNA therapeutics directed at lowering GNAO1 c.607 G>A transcripts.