The coexistence of naturally aged nanoplastics (NPs) and the antioxidant N-cyclohexyl-N'-phenyl-p-phenylenediamine (CPPD) in aquatic environments poses combined risks to ecosystems. This study evaluated the developmental and ocular toxicity of CPPD alone and in co-exposure with two types of aged polystyrene nanoplastics (PS) including ultraviolet-irradiated (PS-UV) and ozonated (PS-O₃) in embryonic zebrafish. Results showed that the presence of aged PS significantly exacerbated CPPD-induced developmental toxicity, manifested as synergistic inhibition of spontaneous movement, touch response, and heart rate, alongside increased malformation rates. Notably, co-exposure aggravated larval ocular abnormalities and visual behavior deficits (light sensitivity and phototaxis), accompanied by increased cell death and inflammation in the ocular region. The combined toxicity of PS-O₃ with CPPD was more potent than that of PS-UV. Mechanistic investigations revealed that the thyroid pathway inhibitor n-phenylthiourea (PTU), but not triiodothyronine (T3), effectively alleviated ocular toxicities. While T3 showed a partial response to CPPD alone, PTU treatment successfully rescued co-exposure-induced apoptosis, aberrant Olig2 and Huc expression, and Mbp suppression in the visual system. ELISA analysis confirmed that PTU restored ATP levels and thyroid hormones (T3, T4, TSH) reduced by co-exposure. qPCR showed that PTU attenuated cyp26a activation (a retinoic acid-metabolizing enzyme) and opn1sw1 suppression (a cone opsin gene). Further Mantel analyses revealed these biomarkers were highly correlated with most ocular development indexes, highlighting their potential as key indicators of early visual toxicity progression. These findings suggest that aged PS amplifies CPPD toxicity through synergistic disruption of oxidative stress, thyroxine axis function, and retinoid/phototransduction pathways, providing new insights for ecological risk assessment.

Nanoplastics and tire-derived chemicals are ubiquitous co-pollutants in aquatic environments, originating from road runoff and posing potential risks to vertebrate development through enhanced bioavailability and synergistic toxicity. Polystyrene nanoplastics (PS) can adsorb hydrophobic organics like the antioxidant N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD), acting as vectors that increase tissue accumulation and exacerbate oxidative stress, while 6PPD alone disrupts mitochondrial function and induces sublethal effects in exposed organisms. The vertebrate eye, with its direct environmental exposure and sensitive neural structures, is particularly vulnerable, yet the combined impact of PS and 6PPD on visual morphogenesis remains underexplored. Here we show that co-exposure to environmentally relevant concentrations of PS (1 mg L-1) and 6PPD (0.1-0.8 mg L-1) markedly potentiates ocular toxicity compared to individual exposures, manifesting as myopia-like malformations, increased cell death, and impaired phototaxis. We integrated phenotypic, histological, and multi-omics analyses using zebrafish embryos as a model. Our results show PS-enhanced bioaccumulation of 6PPD in ocular tissues, leading to severe lens and retinal damage, aberrant vascularization, disrupted myelination, and dysregulated pathways including serine proteolysis, retinoic acid metabolism, and ferroptosis-linked oxidative stress. These findings demonstrate nanoplastic-chemical interactions as an emerging threat to aquatic visual function, with implications for survival behaviors and broader ecosystem health under pervasive pollution.

High-dose ionizing radiation (IR), as encountered in radiotherapy-related and radiological emergency contexts, induces severe acute developmental and neurobehavioral toxicity. However, safe and effective natural radioprotective agents remain limited. Ferulic acid (FA), a natural phenolic compound widely found in medicinal and edible plants, possesses well-established antioxidant and anti-inflammatory properties. Nevertheless, its protective effects and underlying mechanisms against high-dose IR-induced acute in vivo injury remain largely unclear. This study aimed to evaluate the in vivo protective effects of FA against acute IR-induced developmental and neurobehavioral toxicity in zebrafish and to investigate the involvement of apoptosis-related pathways. An acute radiation injury model was established in zebrafish embryos subjected to 1-10 Gy IR treatment, and 2.5 Gy was selected for FA intervention based on the dose-response results. Developmental phenotyping, locomotor activity, and social behavioral assays were conducted to assess IR-induced toxicity. Transcriptomic profiling combined with GO and KEGG enrichment analyses, RT-qPCR validation, and acridine orange staining were performed to explore the potential molecular mechanisms. High-dose IR treatment induced dose-dependent developmental defects, increased mortality, and pronounced locomotor and social behavioral abnormalities in zebrafish larvae. FA treatment significantly alleviated IR-induced developmental toxicity and improved locomotor activity and light-dark transition responses. Transcriptomic analysis showed that FA was associated with broad modulation of IR-responsive gene expression changes, with apoptosis, organelle homeostasis, and cell cycle-related processes identified as major transcriptomic features. Four apoptosis-associated candidate genes (chchd10, dmtf1, rcn3, and nr3c2) were identified and validated under irradiated conditions. FA attenuated the aberrant expression of these genes and reduced excessive apoptosis-associated signals in vivo. Collectively, these findings demonstrate that FA confers significant protection against high-dose IR-induced acute in vivo toxicity, at least in part, in association with apoptosis-related transcriptional modulation and attenuation of apoptosis-associated signals. This study provides mechanistic insights supporting FA as a promising natural radioprotective agent for further evaluation in radiotherapy-related and radiological emergency contexts.

The ecological risks of tire antioxidant 6PPD and its transformed metabolite 6PPD-quinone (6PPDQ) have received high attention. The present study evaluated the developmental neurotoxicity and potential mechanisms under 6PPD or 6PPDQ embryonic exposures in zebrafish. Our findings revealed that embryonic exposure to both compounds suppressed larval locomotion during dark periods, while only 6PPD significantly reduced the larval light stimulus sensitivity and phototactic response. Following recovery to juvenile stages, pretreated fish exhibited heightened anxiety and reduced sociability for both chemicals, aggression was exclusively occurred in 6PPDQ, shoaling pattern was tighter in 6PPDQ but looser in 6PPD. Both compounds elevated larval cell death and oxidative stress while inhibiting cranial development, with 6PPD increasing and 6PPDQ decreasing inter-ocular distance. Transgenic strain analyses demonstrated that 6PPD markedly activated Gfap and Olig2 expression in the eye-brain axis region, whereas 6PPDQ specifically enhanced Olig2 expression in brain region. Retinal müller cells (labeled by Gfap) and cone cell patterns were disrupted exclusively by 6PPD, as was the fan-like lens arrangement visualized via Cms1 mitochondrial labeling. Molecular analyses aligned with these observations that both compounds altered neural development genes (sox2, nrxn2a, rab33a), while 6PPD specifically dysregulated ocular development genes (cyp26a, rlbp1b, rdh5). Conversely, 6PPDQ exhibited stronger activation of xenobiotic metabolism and redox activity genes (cyp1a, gstp1, prdx1, p4ha1a) and uniquely upregulated intestinal immune (ccr9a) and potassium channel (kcnj1a.3) genes expression. In silico affinity analysis corroborated these distinctions, showing 6PPD’s preferential binding to CYP26A and 6PPDQ’s stronger interaction with CYP1A. These findings collectively suggest that 6PPD and 6PPDQ induce divergent neurotoxicity pathways of eye-brain axis disruption and gut-brain communication perturbation, respectively, which likely drive their compound-specific behavioral effects.

The ubiquitous presence of micro-and nanoplastics (MNPs) in the environment and everyday products has attracted global attention for their hazardous risks. However, the effects and underling mechanisms of MNPs chronic exposure on behavioral/visual changes of the adult and offspring remain unclear. The present study investigated the impact of polystyrene (PS) nanoplastics of 80, 200 and 500 nm diameters on zebrafish visual behaviors at an environmentally relevant concentration of 0.1 mg/L. Exposure to PS resulted in zebrafish hyperactivity, enhanced aggression, compacted shoaling and less sociability, and especially suppressed the adult optokinetic response (OKR) and offspring larval phototactic behavior, with the 500 nm PS being the most detrimental. Histopathological analysis showed 500 nm PS caused significant structural damage to the retina's pigment epithelium (RPE), photoreceptor cells (PRC), and crystalline lens. Fluorescence observation found PS accumulation in retinal layers correlated with reduced oligodendrocyte transcription factor 2 (Olig2) in optic nerve. Further transcriptomic analysis of the adult eye tissue revealed that 500 nm PS affected the transforming growth factor β (TGFβ) and phototransduction signaling pathways, dysregulated visual perception and lens development, potentially leading to dysopia in zebrafish. Specifically, TGFβ and its regulated-extracellular matrix/inflammatory factors and crystallin genes were increased, but the visual perception genes were decreased, suggesting the TGFβ-crystallin axis disorders contribute to the eye dysfunction induced by PS exposure. Collectively, our results provide new evidence revealing the molecular mechanisms of PS-induced visual toxicity and neurobehavioral changes highlighting that MNPs may pose a risk to vision health.

P-phenylenediamine antioxidants (PPDs) are widely used in the rubber industry and are increasingly recognized as environmental contaminants, raising concerns about their potential risks to wildlife and human health. Our present study investigated the neurotoxicity of embryonic exposure to a sublethal concentration (0.05 mg/L) of three PPDs (CPPD, IPPD and 77PD) in zebrafish. Our results showed that PPDs impaired the fish growth and induced distinct behavioral alterations. Specifically, CPPD exposure induced hyperactivity, aggression and social deficit. IPPD caused hyperactivity and loose shoaling behavior. And 77PD led to social deficits and reduced social cohesion. Examination of head tissues indicated elevated oxidative stress markers, altered antioxidant enzyme activities, increased neurotransmitter levels and abnormality of neural markers (Gfap/Olig2) using transgenic zebrafish. Histopathological analyses revealed marked intestinal damage including villus structural distortion and reduced mucus secretion. Integrated head-transcriptome and gut-microbiome analyses elucidated compound-specific molecular mechanisms. CPPD and IPPD significantly affected ocular lens development and visual perception pathways, whereas CPPD and 77PD notably disrupted olfactory sensory signaling and G protein-coupled receptor pathways. 16S rDNA sequence indicated PPDs-induced intestinal flora disorder by changing the composition and structure of intestinal flora, where the decreased Firmicutes to Bacteroidetes ratio may account for the fish growth suppression. Dual-omics integration revealed regulatory interactions between brain metabolic genes and gut microbiota, corroborating elevated gut lysozyme activity and increased inflammatory markers (TGFβ, IL6). These gut disturbances were linked to head gene dysregulations (muc5.3, or109 and apip). Additional antibiotic metronidazole (MTZ) treatment alleviated PPDs-induced zebrafish behavioral changes and suppressed the gut-brain stress response indicators. Our findings demonstrate that embryonic PPD exposure induces neurotoxicity mediated through gut-brain axis disruption, providing critical insights into the ecological risks of PPD pollutants.

Ionizing radiation (IR) is a ubiquitous environmental radiation factor with natural and anthropogenic sources. The cumulative discharge of nuclear contaminated water into the ocean by Japan in the recent years has been making the impact of IR on aquatic living organisms a topic of great concern in both academic circles and public opinion. However, sex-specific mechanisms of IR-induced reproductive and offspring developmental toxicity remain poorly understood. Here, we investigated the sexually dimorphic effects of acute X-ray radiation on zebrafish (Danio rerio) reproduction using integrated phenotypic and molecular approaches. Transcriptome analysis revealed striking sexual dimorphism in radiation response, with male gonads showing extensive perturbation compared to female tissues. Female gonads exhibited coordinated protective responses characterized by enhanced immune system activation and membrane integrity maintenance, while male tissues showed significant disruption of iron homeostasis and oxidative stress pathways, particularly in ferroptosis-related genes. Paternal radiation induced more severe reproductive impairment compared to the maternal, as evidenced by reduced egg production and fertilization rates. Using transgenic zebrafish lines, we demonstrated that paternal predominantly drove developmental abnormalities in offspring, including vascular defects, increased immune cell infiltration, and neurological malformations. Radiation specifically damaged sperm morphology and motility. Compared to the ovaries, the testes suffered more severe oxidative damage and stress regulation issues, leading to more significant reproductive developmental disorders. Our findings provide molecular mechanistic evidence for sex-specific radiation sensitivity in aquatic organisms and highlight the importance of considering sexual dimorphism in radiation protection strategies.

As an important psychoactive substance, cotinine is ubiquitous in aquatic environment and poses a threat to aquatic organisms. However, the mechanism of its adverse health impacts remains unclear. We evaluated the effects of cotinine exposure at environmentally relevant concentrations on the development and locomotor behavior of zebrafish ( Danio rerio ) larvae using neurotransmitters and whole endogenous metabolism. Mild developmental toxicity and significant neurobehavior disorder, such as spontaneous movement (1 -1000 mu g/L), 48 hpf tactile response (50, 100, and 1000 mu g/L), and 144 hpf swimming speed (1, 10, 100, 500, and 1000 mu g/L), were observed in zebrafish. Exposure to cotinine led to significant alterations in 11 neurotransmitters, including homogentisic acid, serotonin, glutamic acid and aspartic acid, etc. 298 metabolites were identified and two pathways - linoleic acid metabolism and taurine and hypotaurine metabolism - were delineated. In addition, amino acid neurotransmitters were significantly correlated with metabolites such as arachidonic acid as well as its derivatives, steroidal compounds, and amino acids. Serotonin demonstrates a noteworthy correlation with 31 out of 40 differentially expressed neurotransmitters, encompassing lipids, amino acids, and other compounds. These novel findings contribute to a comprehensive understanding of the ecological risks associated with cotinine contamination in surface waters.

Both dichlorodiphenyltrichloroethane (DDT) and titanium dioxide nanoparticle (TiO2 NP) have worldwide-scale commercial applications, resulting in their co-pollution in the ecosystems and posing combined health risks. However, there is a lack of toxicity studies for the interactions of DDT and TiO2 NP in the environmental relevant concentrations. In this study, we characterized the coexposures using a zebrafish waterborne exposure approach and evaluated the neurotoxicity response of the treated embryos or adults. Our results showed that DDT/TiO2 NP coexposure enhanced the DDT accumulation in vivo and increased the larval locomotor. The chronic DDT/TiO2 NP coexposure did not affect the overall survival rate, sex ratio and growth. However, DDT/TiO2 NP coexposure severely affected the adult locomotor activity, social contact, shoaling and aggressive behaviors compared to single treatment groups or controls. These adult behavioral deficits were accompanied by changes in neurotransmitter acetylcholine (ACH) level in the brain and muscle tissues, as well as neural development genes expression activation of growth-associated protein 43 (gap43) and synaptic vesicle glycoprotein 2 (sv2) in the brain. The significantly increased ACH level and the activated neural genes expression in the DDT/TiO2 NP co-exposed fish may account for the observed hyperactivity and social deficits.

The ubiquitous presence of micro -and nanoplastics (MNPs) in the environment and everyday products has attracted attention due to their hazardous risks. However, the effects of MNPs on reproduction and the underlying mechanisms remain unclear. The present study investigated the impact of polystyrene (PS) nanoplastics of 80, 200 and 500 nm diameters on zebrafish reproduction at an environmentally relevant concentration of 0.5 mg/L. Exposure to PS delayed spermatogenesis and caused aberrant follicular growth, resulting in dysgenesis in F0 adults and impacting F1 embryo development. Notably, the reproductive toxicity exhibited size -dependency, with the 500 nm PS being the most detrimental. Combined analyses of transcriptomics and metabolomics in ovary tissue revealed that treatment with 500 nm PS affected the peroxisome proliferator-activated receptor (PPAR) signaling pathway, dysregulated lipid transport, binding and activity processes, and led to dysgenesis in zebrafish. Specifically, the ovulatory dysfunction induced by PS exposure resembled clinical manifestations of polycystic ovary syndrome (PCOS) and can be attributed to lipid metabolism disorder involving glycerophospholipid, sphingolipid, arachidonic acid, and alpha-linolenic acid. Collectively, our results provide new evidence revealing the molecular mechanisms of PS -induced reproductive toxicity, highlighting that MNPs may pose a risk to female reproductive health.

Dichlorodiphenyltrichloroethane (DDT) is a broad-spectrum insecticide, widely detected in environments due to its high stability characteristic and long natural half-life period. The adverse impact of DDT exposure on organisms and humans has attracted great concern worldwide. The current study explored the developmental and neurobehavioral toxicity response of DDT in embryonic zebrafish. The embryos were treated with DDT (0, 0.1, 1, 2.5 and 5 µM) during 6 h post fertilization (hpf) to 144 hpf. Our result indicated that DDT exposures increased the embryo hatching rate at 48 and 60 hpf, the larval malformation rate at 120 hpf and mortality rate at 144 hpf. The manifested malformations included uninflated swim bladder, bent spine and tail, deformed liver, and pericardial edema. The 120 hpf larval organs size of the gut and swim bladder was decreased in higher exposed concentration groups. Besides, DDT exposure resulted in hyperactivity for the embryo spontaneous movement at 24 hpf and tremor like movement measured by the free larval activity at 72 hpf, as well as the larval activity at 96 hpf under light-dark transition stimulus. Mechanistic examinations at 120 hpf revealed DDT exposure elevated oxidative stress through MDA formation increase, ATP level decrease as well as antioxidant enzyme genes (sod1 and gpx1a) expression decrease. DDT exposure induced abnormal neurotransmitters expression with DA level increase, 5-HT and NOS level decrease. DDT exposure suppressed the gene expressions involved in axon development (rab33a and nrxn2a) and potassium channel (kcnq2 and kcnq3). Our results suggest that the hyperactivity and tremor like movement in DDT-exposed embryos/larvae may result from oxidative stress involved with neuronal damage.

Because of widespread environmental contamination, there is growing concern that nanoplastics may pose a risk to humans and the environment. Due to their small particle size, nanoplastics may cross the blood-nerve barrier and distribute within the nervous system. The present study systematically investigated the uptake/distribution and developmental/neurobehavioral toxicities of different sizes (80, 200, and 500 nm) of polystyrene nanoplastics (PS) in embryonic and juvenile zebrafish. The results indicate that all three sizes of PS could cross the chorion, adsorb by the yolk, and distribute into the intestinal tract, eye, brain, and dorsal trunk of zebrafish, but with different patterns. The organ distribution and observed developmental and neurobehavioral effects varied as a function of PS size. Although all PS exposures induced cell death and inflammation at the cellular level, only exposures to the larger PS resulted in oxidative stress. Meanwhile, exposure to the 80 nm PS increased the expression of neural and optical-specific mRNAs. Collectively, these studies indicate that early life-stage exposures to PS adversely affect zebrafish neurodevelopment and that the observed toxicities are influenced by particle size.

Tea plant (Camellia sinensis) is an important traditional horticultural plant known for the tea products processed from its leaves, which often faces many different adverse conditions, including saline environments. Na+/H+ antiporters (NHXs) are extensively involved in the process of plant response to salt stress and resistance acquisition, but studies in tea plant are less common. In this study, a novel NHX gene named CsNHX6 was cloned from tea plant, which encodes 528 amino acids with 12 typical transmembrane domains. Our results showed that CsNHX6 had both Na+ and K+ dual transport function, and the transport activity depended on an appropriate H+ concentration. In addition, three conserved acidic residues, D164, E188 and D193 in CsNHX6, are essential for Na+ and K+ transport. Further, we found that CsNHX6 was significantly induced by salt stress, and its overexpression enhanced the tolerance of yeast and Arabidopsis to salt stress, this was closely related to the improvement of Na+ storage capacity of cells. Furthermore, subcellular localization assay revealed that CsNHX6 was localized in a Golgi-to-vacuole transport system, including Golgi, TGN, PVC and vacuole, and this localized distribution could be enhanced by salt stress. Taken together, these findings suggest that a potential Na+ transport network is dominated by CsNHX6 under salt stress, which directly or indirectly achieves the regionalization of excessive Na+, thus endowing organisms with salt tolerance.

As ubiquitous contaminants, nanoplastics and antibiotics are frequently co-presence and widely detected in the freshwater environment and biota, posing a high co-exposure risk to aquatic organisms and even humans. More importantly, how the aging process of nanoplastics affects the joint toxic potential of nanoplastics and antibiotics has not been explored. Here, we generated two aged polystyrene nanoplastics (PS) by UV radiation (UV-PS) and ozonation (O3-PS). Non-teratogenic concentrations of pristine PS (80 nm) and antibiotics penicillin (PNC) coexposure synergistically suppressed the embryo heart beating and behaviors of spontaneous movement, touch response, and larval swimming behavioral response. Pristine PS and aged UV-PS, but not aged O3-PS, showed similar effects on zebrafish embryo/larval neurodevelopment. However, when co-exposure with PNC, both aged PS, but not pristine PS, showed antagonistic effects. In late-stage juvenile social behavior testing, we found that PS decreased the exploration in light/dark preference assay. The synergistic effect of aged PS with PNC was further explored, including cellular apoptosis, ROS formation, and neurotransmitter metabolite regulation. Mechanistically, aged UV-PS but not O3-PS significantly increased the adsorption rate of PNC compared to pristine PS, which may account for the toxicity difference between the two aged PS. In conclusion, our results confirmed that PS served as a carrier for PNC, and the environmental aging process changed their neurobehavioral toxicity pattern in vivo.

The automobile tire antioxidant N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine (6PPD) and its quinone metabolite 6PPDQ have recently received much attention for their acute aquatic toxicity. The present study investigated the mechanistic developmental toxicity of 6PPD and 6PPDQ in embryonic zebrafish. Neither compound induced significant mortality but significantly decreased spontaneous embryo movement and heart rate. Both compounds induced malformations with different phenotypes; the 6PPD-exposed larvae manifested a myopia-like phenotype with a convex eyeball and fusion vessels, while the 6PPDQ-exposed embryonic zebrafish manifested enlarged intestine and blood-coagulated gut, activated neutrophils, and overexpressed enteric neurons. mRNA-Seq and quantitative real-time PCR assays showed that 6PPD- and 6PPDQ-induced distinct differential gene expression aligned with their toxic phenotype. 6PPD activated the retinoic acid metabolic gene cyp26a, but 6PPDQ activated adaptive cellular response to xenobiotics gene cyp1a. 6PPD suppressed the gene expression of the eye involved in retinoic acid metabolism, phototransduction, photoreceptor function and visual perception. In contrast, 6PPDQ perturbed genes involved in inward rectifier K+ and voltage-gated ion channels activities, K+ import across the plasma membrane, iron ion binding, and intestinal immune network for IgA production. The current study advances the present understanding the reason of why many fish species are so adversely impacted by 6PPD and 6PPDQ.

Materials and Methods used for experiments in Supplemental Figures and Supplemental References

Supplementary Figures S1-S9

In nature, cold stress is a core threat to aquatic organisms. But the neurodevelopmental effects of cold stress during the perinatal period on the offspring development were unknown. In the present study, adult zebrafish were cold-stressed at 18 degrees C for five days before spawning, and then the fertilized eggs were raised at 18, 24, or 28 degrees C from 0 to 120 h post fertilization (hpf). The resulting embryos and larvae were assessed for developmental and neurobehavioral responses. Our findings showed that embryos raised at 18 degrees C (Cold+++) suffered hatching failure and death, at 24 degrees C (Cold++) had decreased hatching, while those raised at 28 degrees C (Cold+) exhibited no developmental adversity. The neurobehavioral assessment showed that embryos from Cold+ and Cold++ groups displayed decreased motor behaviors, including spontaneous movement at 20-24 hpf, touch response at 48 hpf, and swimming speed at 120 hpf. In addition, cold stress during perinatal stage irreversibly affected larval social behaviors examined during 10-13 days post fertilization (dpf), such as unconsolidated shoaling, increased mirror attacks, and decreased social contacts. Notably, behavioral adversity was more pronounced in larvae from the Cold ++ group than those from the Cold+ group. Mechanistically, cold stress increased cell apoptosis, evidenced by increased acridine orange positive cells at 24 hpf and upregulation of casp8 at 120 hpf, increased oxidative stress (upregulation of cat and nos1) at 120 hpf, delayed motor neuron extension at 72 hpf, and upregulated nrxn2 and rab33a at 120 hpf. Our data indicate that cold stress during the perinatal period impaired neural development in zebrafish larvae, showing high mental health risk. These findings highlight cold stress should be avoided during the perinatal period for both aquatic fish or even humans.

In embryonal rhabdomyosarcoma (ERMS) and generally in sarcomas, the role of wild-type and loss- or gain-of-function TP53 mutations remains largely undefined. Eliminating mutant or restoring wild-type p53 is challenging; nevertheless, understanding p53 variant effects on tumorigenesis remains central to realizing better treatment outcomes. In ERMS, >70% of patients retain wild-type TP53, yet mutations when present are associated with worse prognosis. Employing a kRASG12D-driven ERMS tumor model and tp53 null (tp53-/-) zebrafish, we define wild-type and patient-specific TP53 mutant effects on tumorigenesis. We demonstrate that tp53 is a major suppressor of tumorigenesis, where tp53 loss expands tumor initiation from <35% to >97% of animals. Characterizing three patient-specific alleles reveals that TP53C176F partially retains wild-type p53 apoptotic activity that can be exploited, whereas TP53P153Δ and TP53Y220C encode two structurally related proteins with gain-of-function effects that predispose to head musculature ERMS. TP53P153Δ unexpectedly also predisposes to hedgehog-expressing medulloblastomas in the kRASG12D-driven ERMS-model.