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PubMed2026

Maternal redd1 mRNA decline triggers mTORC1 activation during the blastula-gastrula transition in zebrafish embryos.

During early metazoan development, maternal mRNAs and proteins stored in the egg sustain initial cellular functions. After the blastula stage, developmental control shifts to zygotic gene expression, and maternal transcripts are progressively degraded. Although mTORC1 is a central regulator of global mRNA translation and cell growth, its role in controlling maternal mRNA translation prior to gastrulation remains poorly understood. In zebrafish embryos, the mTORC1 inhibitor redd1 is abundantly expressed after fertilization but decreases following the maternal-to-zygotic transition (MZT), inversely correlating with mTORC1 activity. Overexpression of redd1 suppresses mTORC1, impairs gastrulation, and reduces translation of 5'TOP mRNAs and key regulatory genes, underscoring the necessity of relieving mTORC1 inhibition after the blastula stage. To investigate redd1 translation under conditions of low mTORC1 activity, we injected reporter mRNAs containing its 5' and 3' UTRs. The 3'UTR promoted polyadenylation and enhanced translation, while both UTRs enabled efficient reporter expression despite mTORC1 suppression, indicating that redd1 mRNA is translated independently of canonical mTORC1 pathways. Similarly, maternal mRNAs such as nanog, myca, pou5f3, and ccnb1, as well as the early zygotic transcript dharma, are translated through mTORC1-independent mechanisms. Together, these findings reveal a transient phase of mTORC1 suppression in early zebrafish embryos and demonstrate that select maternal and zygotic mRNAs bypass this regulation to ensure proper developmental progression.

Animals↗

PubMed2025

H3K4me2 marks the enhancer: Enhancer logic in the zebrafish embryo.

At a key point in development, the embryo activates its genome: a shift that is largely coordinated by maternally derived factors. A new study in PLOS Biology identifies H3K4me2-marked enhancers in zebrafish that function independently and mirror the gamete state.

Animals↗

PubMed2026

Integrated experimental and bioinformatics analysis reveals ECM-integrin and redox signaling associated with PMMA/NiO nanocomposites for craniofacial applications.

BACKGROUND: Poly(methyl methacrylate) (PMMA) is widely used in dental and craniofacial applications; however, its clinical performance is limited by poor surface wettability, moderate mechanical strength, and restricted biological activity. Integrating nanomaterial engineering with computational biology offers an opportunity to better understand biomaterial-cell interactions and support the rational design of functional biomaterials. METHODS: Nickel oxide (NiO) nanoparticles were synthesized via chemical precipitation and incorporated into PMMA to fabricate nanocomposites. Physicochemical characterization included contact angle measurements, Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), and Vickers hardness testing. Biocompatibility was evaluated using zebrafish embryo developmental assays. To explore biological processes potentially associated with biomaterial-cell interactions, bioinformatics analyses including Gene Ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), and STRING protein-protein interaction (PPI) network analyses were performed. RESULTS: Incorporation of NiO nanoparticles improved the surface and mechanical properties of PMMA, reducing the contact angle from 105.35° to 90.46° and increasing Vickers hardness compared with unmodified PMMA. Structural and morphological analyses confirmed successful synthesis and homogeneous nanoparticle incorporation. Zebrafish embryo studies demonstrated minimal developmental toxicity, supporting the biocompatibility of the nanocomposite. Bioinformatics analyses identified significant enrichment of pathways related to extracellular matrix organization, cell adhesion, focal adhesion, PI3K-Akt signaling, and oxidative stress regulation. Protein-protein interaction analysis revealed highly interconnected networks associated with ECM-integrin signaling and redox homeostasis, highlighting biological processes potentially associated with biomaterial-cell communication. CONCLUSIONS: PMMA/NiO nanocomposites exhibited improved physicochemical performance and favorable biocompatibility characteristics. The integration of experimental characterization with bioinformatics and network-based analyses provides a systems-level perspective on biomaterial-associated cellular processes and identifies ECM-integrin signaling and oxidative stress-related pathways as candidate biological processes for future experimental validation. These findings support the continued development of PMMA/NiO nanocomposites for oral and craniofacial biomedical applications.

Nanocomposites↗

PubMed2026

First characterization of Staphylococcus felis in diabetic foot osteomyelitis: from intracellular persistence to phage treatment.

Staphylococcus felis is a coagulase-negative Staphylococcus (CoNS) primarily associated with the feline microbiota and only rarely reported in human disease. Here, we report its implication in diabetic foot osteomyelitis, and provide the first comprehensive characterization of its pathogenic potential. Two isolates (NSF001 and NSF002), recovered 5 months apart from bone biopsies of the same patient, were analyzed for growth kinetics, biofilm formation, and intracellular persistence in macrophages and osteoblasts. Both isolates proliferated efficiently, produced robust biofilm, and persisted within host cells, most markedly in osteoblasts. In a zebrafish embryo infection model, both isolates caused significant mortality, confirming their pathogenic potential in vivo. Whole-genome sequencing revealed conserved virulence determinants, a narrow resistome, and strain-specific genomic variations affecting genes involved in virulence regulation, phage defense, and iron acquisition. The lytic phage SAVM02, previously characterized for activity against other Staphylococcus species, effectively inhibited S. felis growth in vitro and conferred protection in vivo against lethal infection. Notably, the two sequential isolates differed in their in vivo virulence and phage susceptibility, paralleling these within-host microevolutionary changes and illustrating bacterial adaptation during chronic infection. Altogether, this study establishes S. felis as a CoNS capable of intracellular persistence, biofilm formation, and in vivo virulence in chronic human infection. Our findings also highlight the therapeutic potential of lytic phages against virulent CoNS species and support further investigation of phage therapy for chronic staphylococcal infections.IMPORTANCECoagulase-negative staphylococci (CoNS) are increasingly recognized as genuine agents of chronic infection, yet the pathogenic capacity of most individual species remains undefined. Staphylococcus felis, a commensal of cats only exceptionally reported in humans, had never been implicated in a chronic human infection. Here, we describe two sequential S. felis isolates recovered from bone biopsies of a patient with diabetic foot osteomyelitis and show that this species combines biofilm formation, intracellular persistence in macrophages and osteoblasts, and lethality in a zebrafish embryo model. Whole-genome comparison of the two isolates uncovered microevolutionary changes, most notably in iron-acquisition and genome-defense loci, that paralleled differences in virulence and phage susceptibility. These findings extend the list of CoNS capable of causing invasive human disease and provide a rationale for lytic phage therapy against emerging, difficult-to-treat staphylococcal pathogens.

Staphylococcus felis↗

PubMed2025

Paired Single-Cell Transcriptome and DNA Barcode Detection in Zebrafish Using ScarTrace.

ScarTrace is a CRISPR/Cas9-based genetic lineage tracing method that allows for uniquely barcoding the DNA of single cells at a target GFP sequence during developing zebrafish embryos. Single cells from barcoded adult zebrafish can be isolated from various tissues (e.g., marrow, brain, eyes, fins), and their transcriptome and barcode sequences are captured by single-cell cDNA amplification and genomic DNA nested PCR, respectively. Computationally, cell type and barcode identification permit clone tracing and lineage tree reconstruction of tissues to unravel fate decisions during embryogenesis.

Animals↗

PubMed2025

The snakehead retrovirus promoter functions independently of the 3'ORF protein and its products are maternally inherited in transgenic zebrafish.

The exogenous snakehead retrovirus (SnRV) is an unclassified member of the Orthoretrovirinae subfamily, discovered in cell lines derived from several fish species. SnRV resembles complex lentiviruses and potentially encodes accessory proteins, including the product of the 3' open reading frame (3'ORF). The 3'ORF protein was suggested to function as a transactivator of transcription (Tat). Here, we constructed an infectious molecular clone for SnRV and tested the effects of 3'ORF mutations on SnRV transcription. Although replacing 3'ORF with foreign sequences strongly reduced virus expression and production, an out-of-frame point mutation in 3'ORF had only a minimal effect on SnRV replication. This latter result suggests that the 3'ORF protein does not function as Tat and that SnRV transcription is largely independent of the product of this ORF. We also show that in vitro, the SnRV promoter is versatile and robustly functioning in both fish and mammalian cultured cells. Finally, the SnRV promoter was transiently active in injected zebrafish embryos as early as the blastula stage. In transgenic zebrafish, this promoter drives enhanced expression in sensory organs and gonads, and its generated products are maternally inherited. Considering these characteristics, the SnRV promoter emerges as a promising candidate for developing versatile expression vectors applicable to research and biotechnological applications.

Animals↗

PubMed2025

H3K4me2 distinguishes a distinct class of enhancers during the maternal-to-zygotic transition.

After egg fertilization, an initially silent embryonic genome is transcriptionally activated during the maternal-to-zygotic transition. In zebrafish, maternal vertebrate pluripotency factors Nanog, Pou5f3 (OCT4 homolog), and Sox19b (SOX2 homolog) (NPS) play essential roles in orchestrating embryonic genome activation, acting as "pioneers" that open condensed chromatin and mediate acquisition of activating histone modifications. However, some embryonic gene transcription still occurs in the absence of these factors, suggesting the existence of other mechanisms regulating genome activation. To identify chromatin signatures of these unknown pathways, we profiled the histone modification landscape of zebrafish embryos using CUT&RUN. Our regulatory map revealed two subclasses of enhancers distinguished by presence or absence of H3K4me2. Enhancers lacking H3K4me2 tend to require NPS factors for de novo activation, while enhancers bearing H3K4me2 are epigenetically bookmarked by DNA hypomethylation to recapitulate gamete activity in the embryo, independent of NPS pioneering. Thus, parallel enhancer activation pathways combine to induce transcriptional reprogramming to pluripotency in the early embryo.

Animals↗

PubMed2027

Genomic Profiling of Chromatin State Using CUT&Tag.

Alterations in chromatin state, mediated through histone modifications and the incorporation of histone variants, are fundamental to establishing transcriptional networks and cell identity. Recent advances in low-input epigenome profiling methods, such as CUT&Tag and CUT&RUN, have enabled the study of chromatin states from very limited starting materials. In this chapter, we describe procedures for generating CUT&Tag libraries to profile histone modifications and histone variants in early-developing zebrafish embryos.

Animals↗

PubMed2026

Neurodevelopmental toxicity of 2-(Methylthio)benzothiazole (MTBT) in zebrafish: Insights into PTGS2- associated dysregulation of the neuroactive ligand-receptor interaction pathway.

2-(Methylthio)benzothiazole (MTBT), an important derivative of benzothiazoles, has extensive applications in industrial processes, pharmaceuticals, and environmental monitoring. It can enter aquatic environments through surface runoff and has been detected at relatively high concentrations in various environmental systems. However, studies investigating the aquatic toxicity of MTBT remain limited. In this study, zebrafish embryos were exposed to MTBT at concentrations of 0, 10, 100, and 1000 μg/L for 144 h to evaluate its developmental and neurotoxic effects. MTBT exposure significantly reduced the survival rate, hatching rate, spontaneous movement, and body length of zebrafish larvae. MTBT also impaired locomotor behavior, reduced fluorescence of Tg(huc:eGFP) larvae in the central nervous system and inhibited motor neuron axonal development. Protein-protein interaction network and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses indicated that MTBT-induced neurotoxicity may be associated with disruption of the neuroactive ligand-receptor interaction pathway. Further validation experiments revealed that MTBT induced oxidative stress, inflammation, and apoptosis, suggesting that these adverse effects may underlie its neurodevelopmental toxicity. Collectively, these findings provide biological evidence that MTBT induces neurodevelopmental toxicity in zebrafish larvae and suggest that dysregulation of the PTGS2-related neuroactive ligand-receptor interaction pathway may be involved in this process.

2-(Methylthio)benzothiazole (MTBT)↗

PubMed2026

Defining active and repressive chromatin states in neural crest cells using low-input CUT&RUN.

The transition of neural crest cells (NCCs) from a multipotent state to lineage-restricted derivatives, including melanocytes, is governed by tightly regulated epigenetic mechanisms that orchestrate cell type specific gene expression programs. Histone post-translational modifications (PTMs), in particular, play an important role in modulating chromatin accessibility, enhancer activation, and transcription factor occupancy, thereby facilitating dynamic chromatin and transcriptional reprogramming required during development. However, profiling such chromatin states in rare and transient Neural Crest Cell (NCC) populations in vivo remains technically challenging. To address this, we present an optimized low-input Cleavage Under Targets and Release Using Nuclease (CUT&RUN) workflow tailored for fluorescence-activated cell sorting (FACS) isolated NCCs from zebrafish embryos. This approach enables high-resolution and low-background mapping of key histone modifications, including H3K27ac, H3K4me3, and H3K27me3, from limited cell numbers. Collectively, these methodologies provide a robust framework for dissecting chromatin state dynamics in developmental systems and can also offer insights into epigenetic dysregulation associated with disease.

Animals↗

PubMed2026

Pseudomonas aeruginosa mgtC gene is under the control of PhoP and CbrAB regulators, and its expression can be visualized in macrophages.

The MgtC virulence factor is important during the intramacrophage stage in both classical intracellular pathogens, such as Salmonella Typhimurium, and in extracellular bacteria that transiently encounter intracellular environments during infection, such as Pseudomonas aeruginosa. In these different pathogens, mgtC expression is induced in vitro by magnesium ion depletion, a condition reported to mimic the macrophage environment. Here, we developed an unstable GFP reporter system to monitor in real time the transcriptional activation of the P. aeruginosa mgtC promoter. After in vitro validation in magnesium-defined media, this reporter system allowed visualization of the mgtC promoter induction in a subset of bacteria when P. aeruginosa localized inside cultured macrophages. In addition, although rare under our experimental conditions, in vivo activation of the mgtC promoter was observed for the first time within macrophages of live, infected zebrafish larvae, a cutting-edge vertebrate model for real-time imaging. While MgtC regulation in Salmonella is mediated by the magnesium-responsive PhoPQ two-component system, its regulation in P. aeruginosa remained unknown. The use of mutant strains for two-component regulatory systems revealed that the PhoP regulator, but not by its cognate sensor PhoQ, was required to activate P. aeruginosa MgtC expression in vitro. Unexpectedly, CbrAB, a two-component system specific to Pseudomonas species, was also involved in P. aeruginosa MgtC regulation. Both PhoP and CbrB regulatory proteins were found to directly bind the mgtC promoter, supporting a dual transcriptional control. These findings reveal substantial differences in mgtC gene regulation in different bacterial pathogens, reflecting distinct strategies to drive appropriate expression of a shared virulence factor involved in macrophage adaptation.IMPORTANCEThe adaptation of bacterial pathogens to the host intracellular microenvironment requires tight and rapid regulation of specific genes, and investigating the in vivo transcriptional dynamics of such genes is a major challenge. Here, we focused on the expression of mgtC, a gene important for adaptation to the intramacrophage environment in classical intracellular pathogens, such as Salmonella Typhimurium, and bacteria with a transient intracellular lifestyle, such as Pseudomonas aeruginosa. An unstable GFP reporter system was designed to monitor the transcriptional dynamics of P. aeruginosa mgtC. The use of this reporter system in a state-of-the-art vertebrate model for live imaging, the zebrafish embryo, allowed in vivo tracking of P. aeruginosa mgtC promoter activation inside macrophages in a living host. Furthermore, the expression of P. aeruginosa mgtC was found to be regulated through a mechanism distinct from that of Salmonella MgtC, since it involves the PhoP regulatory protein, but not the PhoQ sensor, and the Pseudomonas-specific CbrAB two-component system, reflecting diverse, finely tuned strategies to control a virulence factor shared by several major human pathogens.

Pseudomonas aeruginosa↗

PubMed2024

Cilia defects upon loss of WDR4 are linked to proteasomal hyperactivity and ubiquitin shortage.

The WD repeat-containing protein 4 (WDR4) has repeatedly been associated with primary microcephaly, a condition of impaired brain and skull growth. Often, faulty centrosomes cause microcephaly, yet aberrant cilia may also be involved. Here, we show using a combination of approaches in human fibroblasts, zebrafish embryos and patient-derived cells that WDR4 facilitates cilium formation. Molecularly, we associated WDR4 loss-of-function with increased protein synthesis and concomitant upregulation of proteasomal activity, while ubiquitin precursor pools are reduced. Inhibition of proteasomal activity as well as supplementation with free ubiquitin restored normal ciliogenesis. Proteasome inhibition ameliorated microcephaly phenotypes. Thus, we propose that WDR4 loss-of-function impairs head growth and neurogenesis via aberrant cilia formation, initially caused by disturbed protein and ubiquitin homeostasis.

Animals↗

PubMed2026

Stem Cell Differentiation Disperses Transcriptional Clusters via a Conserved Surface-Condensate Trajectory.

Stem cells exhibit exceptionally prominent transcriptional clusters, which dissolve with progressing differentiation. Although these clusters are assigned central roles in embryonic gene regulation, their formation and loss during differentiation remain poorly understood. This study reveals that these prominent clusters disperse along a conserved trajectory in mouse embryonic stem cells, fruit fly testes, and zebrafish embryos. Imaging and lattice simulations show that these clusters form via surface condensation on H3K27ac-marked super-enhancer regions, which act as genomic scaffolds. Upon differentiation, partial loss of these active epigenetic marks and transcription-driven unfolding lead to dispersal of the prominent clusters. The block copolymer-based lattice simulations explain this process as a conserved trajectory through a three-dimensional state space, governed by surface condensation principles that extend beyond canonical liquid-liquid phase separation. This work marks surface condensation as a biophysical mechanism for the dynamic organization of stem cell-specific transcriptional hubs and demonstrates evolutionary conservation in several organisms. By uncovering a conserved biophysical mechanism for transcriptional organization in development, our work illustrates how polymer properties can contribute to the control of cell identity and fate.

Animals↗

PubMed2025

Extrusion fountains are hallmarks of chromosome organization emerging upon zygotic genome activation.

The initiation of gene expression during development, known as zygotic genome activation (ZGA), is accompanied by massive changes in chromosome organization. However, the earliest events of chromosome folding and their functional roles remain unclear. Using Hi-C on zebrafish embryos, we discovered that chromosome folding begins early in development with the formation of "fountains", a novel element of chromosome organization. Emerging preferentially at enhancers, fountains exhibit an initial accumulation of cohesin, which later redistributes to CTCF sites at TAD borders. Knockouts of pioneer transcription factors driving ZGA enhancers result in the specific loss of fountains, establishing a causal link between enhancer activation and fountain formation. Polymer simulations demonstrate that fountains may arise as sites of facilitated cohesin loading, requiring two-sided but desynchronized loop extrusion, potentially caused by cohesin collisions with obstacles or internal switching. Moreover, we detected similar fountain patterns at enhancers in mouse cells. Fountains disappear upon acute cohesin depletion, as well as during mitosis, and reappear with cohesin loading in early G1. Altogether, fountains represent the first known enhancer-specific elements of chromosome organization and constitute starting points for chromosome folding during development, likely through facilitated cohesin loading.

Journal Article↗

PubMed2018

Thioredoxin interacting protein promotes invasion in hepatocellular carcinoma.

BACKGROUND: Considerable evidence suggests that oxidative stress plays an essential role in the progression of hepatocellular carcinoma (HCC). While acquired resistance to oxidative stress is the main driver of aggressive cell phenotype, the underlying mechanisms remain unknown. Here, we tested the hypothesis that elevated expression of Thioredoxin-interacting protein (TXNIP) is a main regulator of the aggressive phenotype in HCC. MATERIALS AND METHODS: To test this hypothesis, we measured TXNIP expression levels in 11 HCC cell lines by qPCR and western blotting. In addition, 80 pairs of HCC tissues and matched liver tissues of 73 cases, as well as 11 normal liver tissue samples were examined by immunohistochemistry. Besides, TXNIP expression levels were analyzed by Oncomine Platform in seven independent microarray datasets. Finally, the functional role of TXNIP in HCC was investigated in vitro and in vivo by silencing and overexpression studies. RESULTS: Our results show that TXNIP expression is significantly increased in HCC compared to non-tumor counterparts (p < 0.0001) as well as to normal (p < 0.0001) and cirrhotic (p < 0.0001) liver tissues. Moreover, stable overexpression of TXNIP in HCC cells (i) significantly increases ROS levels, (ii) induces EMT phenotype, (iii) increases motility, invasion and 3D branching tubulogenesis, (iv) decreases apoptosis, and (v) elevates in vivo metastasis in zebrafish embryos. Finally, we identify sinusoidal/stromal and cytoplasmic TXNIP staining patterns as risk factors for intrahepatic vascular invasion (p:0.0400). CONCLUSION: Our results strongly suggest that overexpression of TXNIP has a pivotal role in HCC progression by inducing cell survival, invasion, and metastasis.

EMT↗

PubMed2026

A User-Friendly Protocol for Microinjection into Teleost Embryos to Study Gene Function.

Zebrafish (Danio rerio) and medaka (Oryzias latipes) are popular teleost models used in developmental biology and functional genomics. To achieve high-quality and reproducible microinjections, it is essential to have robust protocols for breeding, egg collection, and the precise delivery of genetic material. In this protocol, we present a comprehensive and optimized methodology for setting up breeding tanks under controlled photoperiod conditions to maximize egg yield while minimizing contamination. We provide detailed procedures for sex identification, pair selection, the use of grated breeding inserts, and methods to increase egg collection efficiency. We outline procedures for making injection gel beds, pulling needles, and calibration using one-microliter microcapillaries to achieve consistent nanoliter-scale injections. Our protocol outlines settings for the pico-liter injector that are optimized to deliver a precise amount per pulse with minimal variability. Finally, we demonstrate the application of these methods for gene knockdown using morpholino antisense oligonucleotides, gene knockout using CRISPR-Cas9, and gain-of-function mRNA overexpression experiments. Phenotypic assessments conducted at various developmental stages to evaluate gene-specific effects reveal consistent phenotypic outcomes between the morpholino and CRISPR-Cas9 approaches. This easy and comprehensive protocol enables efficient, precise, and scalable genetic manipulation of zebrafish and medaka embryos, thereby supporting advanced functional studies in developmental biology and disease modeling. To our knowledge, this is the first unified protocol for both zebrafish and medaka microinjection systems achieving 97.7% phenotype penetrance in CRISPR-Cas9 knockouts with precision together with a triple validation approach that confirms gene function across multiple techniques.

Animals↗

PubMed2025

Toxicological Assessment of Melamine-Functionalized Graphene Oxide and Carbon Nanotubes Using Zebrafish Models.

Graphene oxide (GO) and carbon nanotube (CNT)-based nanomaterials have attracted significant interest in various industrial and biomedical applications due to their unique physicochemical properties; however, concerns about their potential toxicity, especially when modified with additives like melamine (M), remain largely unresolved. This study investigates the toxicological effects and underlying mechanisms of graphene oxide-melamine (GO-M) and carbon nanotube-melamine (CNT-M) nanoparticles in zebrafish (Danio rerio) embryos and larvae. To this end, developmental toxicity, phenotypic and behavioral changes, as well as histopathological and immunofluorescence alterations, were evaluated following acute exposure to GO-M and CNT-M nanoparticles at concentrations of 5, 10, and 20 mg/L. Results showed that both nanoparticles delayed larval hatching, particularly at higher concentrations (10 and 20 mg/L). Malformations were observed at 20 mg/L in the GO-M group and at 10 and 20 mg/L in the CNT-M group. Additionally, significant changes in larval length and eye area were observed at all concentrations for both nanoparticles. Behavioral assessments revealed that CNT-M exposure at 10 and 20 mg/L significantly impaired head sensorimotor reflexes, while all concentrations affected tail reflexes. In contrast, GO-M exposure did not significantly alter sensorimotor responses. These findings suggest differential toxic mechanisms and neurobehavioral effects of GO-M and CNT-M nanoparticles during early zebrafish development.

Animals↗

PubMed2025

Low-temperature embryo incubation suppresses off-target mutagenesis during CRISPR-Cas9 genome editing in medaka (Oryzias latipes) and zebrafish (Danio rerio).

Gene knockout using CRISPR-Cas9 is often employed in research aimed at elucidating gene functions in fish. However, CRISPR-Cas9 sometimes introduces unintended alterations, known as off-target mutations. These mutations can reduce the robustness of data during phenotypic analysis. In this study, we focused on the culture temperature, which is known to significantly influence mutagenesis, and examined whether low-temperature culture after introducing CRISPR-Cas9 into early embryos of medaka and zebrafish suppresses off-target mutations. Continuous incubation of medaka at 16 °C significantly reduced off-target mutation rates compared to those at 28 °C; the drawback is that it decreased the survival rate of medaka embryos. Therefore, low-temperature incubation was limited to early development in both zebrafish and medaka, and then the temperature was increased to 28 °C. Under these conditions, the mutation rates of the three off-target regions in medaka (Off-D, Off-P, and Off-A) significantly decreased, whereas those of the three target regions (DJ-1, p4hb, and avt) were unaffected. Similarly, the mutation rate of the zebrafish target region (ywhaqa) remained high, whereas the off-target (Off-Y1) mutation rate significantly reduced. Furthermore, this method effectively suppressed the germ line transmission of off-target mutations in medaka. This approach is effective to obtain more reliable data from the G0 generation of medaka and zebrafish and may reduce the screening effort required to remove individuals with off-target mutations in the F1 generation.

Animals↗