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1.
Nat Commun ; 11(1): 4505, 2020 09 09.
Artigo em Inglês | MEDLINE | ID: mdl-32908148

RESUMO

Evidence for transgenerational inheritance of epigenetic information in vertebrates is scarce. Aberrant patterns of DNA methylation in gametes may set the stage for transmission into future generations. Here, we describe a viable hypomorphic allele of dnmt1 in zebrafish that causes widespread demethylation of CpG dinucleotides in sperm and somatic tissues. We find that homozygous mutants are essentially normal, with the exception of drastically impaired lymphopoiesis, affecting both larval and adult phases of T cell development. The phenotype of impaired larval (but not adult) T cell development is transmitted to subsequent generations by genotypically wildtype fish. We further find that about 200 differentially methylated regions in sperm DNA of transmitting and non-transmitting males, including hypermethylated sites associated with runx3 and rptor genes, whose reduced activities are associated with impaired larval T cell development. Our results indicate a particular sensitivity of larval T cell development to transgenerationally inherited epimutations.


Assuntos
Diferenciação Celular/genética , Genes Recessivos , Larva/crescimento & desenvolvimento , Linfopoese/genética , Linfócitos T/fisiologia , Alelos , Animais , Animais Geneticamente Modificados , Subunidade alfa 3 de Fator de Ligação ao Core/genética , DNA (Citosina-5-)-Metiltransferase 1/genética , DNA (Citosina-5-)-Metiltransferase 1/metabolismo , Metilação de DNA , Epigênese Genética , Feminino , Genética , Larva/citologia , Masculino , Mutação , Proteína Regulatória Associada a mTOR/genética , Espermatozoides/metabolismo , Peixe-Zebra/genética , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
2.
Ecotoxicol Environ Saf ; 205: 111339, 2020 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-32961491

RESUMO

Famoxadone-cymoxanil is a new protective and therapeutic fungicide, but little research has been done on it or its toxicity in aquatic organisms. In this study, we used zebrafish to investigate the cardiotoxicity of famoxadone-cymoxanil and the potential mechanisms involved. Zebrafish embryos were exposed to different concentrations of famoxadone-cymoxanil until 72 h post-fertilization (hpf), then changes of heart morphology in zebrafish embryos were observed. We also detected the levels of oxidative stress, myocardial-cell proliferation and apoptosis, ATPase activity, and the expression of genes related to the cardiac development and calcium-signaling pathway. After famoxadone-cymoxanil exposure, pericardial edema, cardiac linearization, and reductions in the heart rate and cardiac output positively correlated with concentration. Although myocardial-cell apoptosis was not detected, proliferation of the cells was severely reduced and ATPase activity significantly decreased, resulting in a severe deficiency in heart function. In addition, indicators of oxidative stress changed significantly after exposure of the embryos to the fungicide. To better understand the possible molecular mechanisms of cardiovascular toxicity in zebrafish, we studied the transcriptional levels of cardiac development, calcium-signaling pathways, and genes associated with myocardial contractility. The mRNA expression levels of key genes in heart development were significantly down-regulated, while the expression of genes related to the calcium-signaling pathway (ATPase [atp2a1], cardiac troponin C [tnnc1a], and calcium channel [cacna1a]) was significantly inhibited. Expression of klf2a, a major endocardial flow-responsive gene, was also significantly inhibited. Mechanistically, famoxadone-cymoxanil toxicity might be due to the downregulation of genes associated with the calcium-signaling pathway and cardiac muscle contraction. Our results found that famoxadone-cymoxanil exposure causes cardiac developmental toxicity and severe energy deficiency in zebrafish.


Assuntos
Acetamidas/toxicidade , Embrião não Mamífero/efeitos dos fármacos , Fungicidas Industriais/toxicidade , Coração/efeitos dos fármacos , Estrobilurinas/toxicidade , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/metabolismo , Animais , Apoptose/efeitos dos fármacos , Sinalização do Cálcio/efeitos dos fármacos , Sinalização do Cálcio/genética , Cardiotoxicidade , Regulação para Baixo , Embrião não Mamífero/metabolismo , Embrião não Mamífero/patologia , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Coração/embriologia , Frequência Cardíaca/efeitos dos fármacos , Fatores de Transcrição Kruppel-Like/genética , Fatores de Transcrição Kruppel-Like/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Peixe-Zebra/crescimento & desenvolvimento , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
3.
PLoS One ; 15(7): e0225351, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32735563

RESUMO

Endothelial cilia are found in a variety of tissues including the cranial vasculature of zebrafish embryos. Recently, endothelial cells in the developing mouse retina were reported to also possess primary cilia that are potentially involved in vascular remodeling. Fish carrying mutations in intraflagellar transport (ift) genes have disrupted cilia and have been reported to have an increased rate of spontaneous intracranial hemorrhage (ICH), potentially due to disruption of the sonic hedgehog (shh) signaling pathway. However, it remains unknown whether the endothelial cells forming the retinal microvasculature in zebrafish also possess cilia, and whether endothelial cilia are necessary for development and maintenance of the blood-retinal barrier (BRB). In the present study, we found that the endothelial cells lining the zebrafish hyaloid vasculature possess primary cilia during development. To determine whether endothelial cilia are necessary for BRB integrity, ift57, ift88, and ift172 mutants, which lack cilia, were crossed with the double-transgenic zebrafish strain Tg(l-fabp:DBP-EGFP;flk1:mCherry). This strain expresses a vitamin D-binding protein (DBP) fused to enhanced green fluorescent protein (EGFP) as a tracer in the blood plasma, while the endothelial cells forming the vasculature are tagged by mCherry. The Ift mutant fish develop a functional BRB, indicating that endothelial cilia are not necessary for early BRB integrity. Additionally, although treatment of zebrafish larvae with Shh inhibitor cyclopamine results in BRB breakdown, the Ift mutant fish were not sensitized to cyclopamine-induced BRB breakdown.


Assuntos
Barreira Hematorretiniana/metabolismo , Cílios/metabolismo , Células Endoteliais/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Animais Geneticamente Modificados , Barreira Hematorretiniana/efeitos dos fármacos , Barreira Hematorretiniana/fisiologia , Células Endoteliais/citologia , Proteínas Hedgehog/antagonistas & inibidores , Proteínas Hedgehog/genética , Proteínas Hedgehog/metabolismo , Larva/metabolismo , Mutagênese , Vasos Retinianos/citologia , Transdução de Sinais , Alcaloides de Veratrum/farmacologia , Peixe-Zebra/crescimento & desenvolvimento , Peixe-Zebra/metabolismo , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
4.
Sheng Wu Gong Cheng Xue Bao ; 36(7): 1450-1458, 2020 Jul 25.
Artigo em Chinês | MEDLINE | ID: mdl-32748603

RESUMO

Heparin and heparan sulfate are a class of glycosaminoglycans for clinical anticoagulation. Heparosan N-sulfate-glucuronate 5-epimerase (C5, EC 5.1.3.17) is a critical modifying enzyme in the synthesis of heparin and heparan sulfate, and catalyzes the inversion of carboxyl group at position 5 on D-glucuronic acid (D-GlcA) of N-sulfoheparosan to form L-iduronic acid (L-IdoA). In this study, the heparin C5 epimerase gene Glce from zebrafish was expressed and molecularly modified in Escherichia coli. After comparing three expression vectors of pET-20b (+), pET-28a (+) and pCold Ⅲ, C5 activity reached the highest ((1 873.61±5.42) U/L) with the vector pCold Ⅲ. Then we fused the solution-promoting label SET2 at the N-terminal for increasing the soluble expression of C5. As a result, the soluble protein expression was increased by 50% compared with the control, and the enzyme activity reached (2 409±6.43) U/L. Based on this, site-directed mutations near the substrate binding pocket were performed through rational design, the optimal mutant (V153R) enzyme activity and specific enzyme activity were (5 804±5.63) U/L and (145.1±2.33) U/mg, respectively 2.41-fold and 2.28-fold of the original enzyme. Modification and expression optimization of heparin C5 epimerase has laid the foundation for heparin enzymatic catalytic biosynthesis.


Assuntos
Carboidratos Epimerases/biossíntese , Carboidratos Epimerases/química , Heparina/metabolismo , Proteínas de Peixe-Zebra/biossíntese , Proteínas de Peixe-Zebra/química , Animais , Carboidratos Epimerases/genética , Escherichia coli , Expressão Gênica , Heparitina Sulfato/metabolismo , Ácido Idurônico/metabolismo , Proteínas de Peixe-Zebra/genética
5.
PLoS One ; 15(7): e0232559, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32658922

RESUMO

PRESENILIN 2 (PSEN2) is one of the genes mutated in early onset familial Alzheimer's disease (EOfAD). PSEN2 shares significant amino acid sequence identity with another EOfAD-related gene PRESENILIN 1 (PSEN1), and partial functional redundancy is seen between these two genes. However, the complete range of functions of PSEN1 and PSEN2 is not yet understood. In this study, we performed targeted mutagenesis of the zebrafish psen2 gene to generate a premature termination codon close downstream of the translation start with the intention of creating a null mutation. Homozygotes for this mutation, psen2S4Ter, are viable and fertile, and adults do not show any gross psen2-dependent pigmentation defects, arguing against significant loss of γ-secretase activity. Also, assessment of the numbers of Dorsal Longitudinal Ascending (DoLA) interneurons that are responsive to psen2 but not psen1 activity during embryogenesis did not reveal decreased psen2 function. Transcripts containing the S4Ter mutation show no evidence of destabilization by nonsense-mediated decay. Forced expression in zebrafish embryos of fusions of psen2S4Ter 5' mRNA sequences with sequence encoding enhanced green fluorescent protein (EGFP) indicated that the psen2S4Ter mutation permits utilization of cryptic, novel downstream translation start codons. These likely initiate translation of N-terminally truncated Psen2 proteins lacking late endosomal/lysosomal localization sequences and that obey the "reading frame preservation rule" of PRESENILIN EOfAD mutations. Transcriptome analysis of entire brains from a 6-month-old family of wild type, heterozygous and homozygous psen2S4Ter female siblings revealed profoundly dominant effects on gene expression likely indicating changes in ribosomal, mitochondrial, and anion transport functions.


Assuntos
Códon de Terminação/genética , Perfilação da Expressão Gênica , Mitocôndrias/genética , Mutação , Presenilina-2/genética , Ribossomos/genética , Proteínas de Peixe-Zebra/genética , Alelos , Animais , Contagem de Células , Homozigoto , Hipóxia/genética , Neurônios/citologia , Estabilidade de RNA/genética , Peixe-Zebra/embriologia , Peixe-Zebra/genética
6.
Nat Commun ; 11(1): 3698, 2020 07 23.
Artigo em Inglês | MEDLINE | ID: mdl-32703943

RESUMO

Intellectual disability (ID) is a heterogeneous clinical entity and includes an excess of males who harbor variants on the X-chromosome (XLID). We report rare FAM50A missense variants in the original Armfield XLID syndrome family localized in Xq28 and four additional unrelated males with overlapping features. Our fam50a knockout (KO) zebrafish model exhibits abnormal neurogenesis and craniofacial patterning, and in vivo complementation assays indicate that the patient-derived variants are hypomorphic. RNA sequencing analysis from fam50a KO zebrafish show dysregulation of the transcriptome, with augmented spliceosome mRNAs and depletion of transcripts involved in neurodevelopment. Zebrafish RNA-seq datasets show a preponderance of 3' alternative splicing events in fam50a KO, suggesting a role in the spliceosome C complex. These data are supported with transcriptomic signatures from cell lines derived from affected individuals and FAM50A protein-protein interaction data. In sum, Armfield XLID syndrome is a spliceosomopathy associated with aberrant mRNA processing during development.


Assuntos
Proteínas de Ligação a DNA/genética , Deficiência Intelectual/genética , Retardo Mental Ligado ao Cromossomo X/genética , Mutação/genética , Proteínas de Ligação a RNA/genética , Spliceossomos/metabolismo , Proteínas de Peixe-Zebra/genética , Adulto , Animais , Núcleo Celular/metabolismo , Criança , Pré-Escolar , Família , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Masculino , Camundongos , Mutação de Sentido Incorreto/genética , Células NIH 3T3 , Linhagem , Fenótipo , Transporte Proteico , Processamento de RNA/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Nuclear Pequeno/genética , Síndrome , Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
7.
Nat Commun ; 11(1): 3317, 2020 07 03.
Artigo em Inglês | MEDLINE | ID: mdl-32620775

RESUMO

Oriented cell division is a fundamental mechanism to control asymmetric stem cell division, neural tube elongation and body axis extension, among other processes. During zebrafish gastrulation, when the body axis extends, dorsal epiblast cells display divisions that are robustly oriented along the animal-vegetal embryonic axis. Here, we use a combination of lipidomics, metabolic tracer analysis and quantitative image analysis to show that sphingolipids mediate spindle positioning during oriented division of epiblast cells. We identify the Wnt signaling as a regulator of sphingolipid synthesis that mediates the activity of serine palmitoyltransferase (SPT), the first and rate-limiting enzyme in sphingolipid production. Sphingolipids determine the palmitoylation state of the Anthrax receptor, which then positions the mitotic spindle of dividing epiblast cells. Our data show how Wnt signaling mediates sphingolipid-dependent oriented division and how sphingolipids determine Anthrax receptor palmitoylation, which ultimately controls the activation of Diaphanous to mediate spindle rotation and oriented mitosis.


Assuntos
Embrião não Mamífero/metabolismo , Mitose , Receptores de Peptídeos/metabolismo , Esfingolipídeos/metabolismo , Via de Sinalização Wnt , Sequência de Aminoácidos , Animais , Divisão Celular Assimétrica/genética , Embrião não Mamífero/citologia , Embrião não Mamífero/embriologia , Gastrulação , Regulação da Expressão Gênica no Desenvolvimento , Camadas Germinativas/citologia , Camadas Germinativas/embriologia , Camadas Germinativas/metabolismo , Lipoilação , Tubo Neural/citologia , Tubo Neural/embriologia , Tubo Neural/metabolismo , Receptores de Peptídeos/genética , Homologia de Sequência de Aminoácidos , Serina C-Palmitoiltransferase/genética , Serina C-Palmitoiltransferase/metabolismo , Fuso Acromático/metabolismo , Peixe-Zebra , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
8.
Aquat Toxicol ; 225: 105547, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32623180

RESUMO

Some chemicals in the environment disrupt thyroid hormone (TH) systems leading to alterations in organism development, but their effect mechanisms are poorly understood. In fish, this has been limited by a lack of fundamental knowledge on thyroid gene ontogeny and tissue expression in early life stages. Here we established detailed expression profiles for a suite of genes in the hypothalamic-pituitary-thyroid (HPT) axis of zebrafish (Danio rerio) between 24-120 h post fertilisation (hpf) and quantified their responses following exposure to 3,3',5-triiodo-L-thyronine (T3) using whole mount in situ hybridisation (WISH) and qRT-PCR (using whole-body extracts). All of the selected genes in the HPT axis demonstrated dynamic transcript expression profiles across the developmental stages examined. The expression of thyroid receptor alpha (thraa) was observed in the brain, gastrointestinal tract, craniofacial tissues and pectoral fins, while thyroid receptor beta (thrb) expression occurred in the brain, otic vesicles, liver and lower jaw. The TH deiodinases (dio1, dio2 and dio3b) were expressed in the liver, pronephric ducts and brain and the patterns differed depending on life stage. Both dio1 and dio2 were also expressed in the intestinal bulb (96-120 hpf), and dio2 expression occurred also in the pituitary (48-120 hpf). Exposure of zebrafish embryo-larvae to T3 (30 and 100 µg L-1) for periods of 48, 96 or 120 hpf resulted in the up-regulation of thraa, thrb, dio3b, thyroid follicle synthesis proteins (pax8) and corticotropin-releasing hormone (crhb) and down-regulation of dio1, dio2, glucuronidation enzymes (ugt1ab) and thyroid stimulating hormone (tshb) (assessed via qRT-PCR) and responses differed across life stage and tissues. T3 induced thraa expression in the pineal gland, pectoral fins, brain, somites, gastrointestinal tract, craniofacial tissues, liver and pronephric ducts. T3 enhanced thrb expression in the brain, jaw cartilage and intestine, while thrb expression was suppressed in the liver. T3 exposure suppressed the transcript levels of dio1 and dio2 in the liver, brain, gastrointestinal tract and craniofacial tissues, while dio2 signalling was also suppressed in the pituitary gland. Dio3b expression was induced by T3 exposure in the jaw cartilage, pectoral fins and brain. The involvement of THs in the development of numerous body tissues and the responsiveness of these tissues to T3 in zebrafish highlights their potential vulnerability to exposure to environmental thyroid-disrupting chemicals.


Assuntos
Tri-Iodotironina/toxicidade , Poluentes Químicos da Água/toxicidade , Animais , Hormônio Liberador da Corticotropina , Hipotálamo/efeitos dos fármacos , Larva/efeitos dos fármacos , Hipófise/efeitos dos fármacos , Glândula Tireoide/efeitos dos fármacos , Hormônios Tireóideos/metabolismo , Tironinas/metabolismo , Tironinas/farmacologia , Tireotropina , Peixe-Zebra/fisiologia , Proteínas de Peixe-Zebra/genética
9.
Aquat Toxicol ; 225: 105524, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32610223

RESUMO

In the present research, the effects of exposure to a sublethal concentration of zinc (Zn) on metal and ion homeostasis, and the regulation and the localization of various Zn transporters (i.e., the Zrt-Irt Like Protein (ZIP) family of Zn transporters), were investigated in zebrafish (Danio rerio) during early development. Exposure to an elevated level of Zn [4 µM (high) vs. 0.25 µM (control)] from 0 day post-fertilization (dpf) resulted in a significant increase in the whole body content of Zn at 5 dpf. A transient decrease in the whole body calcium (Ca) level was observed in 3 dpf larvae exposed to high Zn. Similarly, whole body nickel (Ni) and copper (Cu) contents were also reduced in 3 dpf larvae exposed to high Zn. Importantly, the magnitude of reduction in whole body Ni and Cu contents following Zn exposure was markedly higher than that in Ca content, suggesting that internal Ni and Cu balance were likely more sensitive to Zn exposure in developing zebrafish. Exposure to high Zn altered the mRNA expression levels of specific zip transporters, with an increase in zip1 (at 3 dpf) and zip8 (at 5 dpf), and a decrease in zip4 (at 5 dpf). The expression levels of most zip transporters tended to decrease from 3 dpf to 5 dpf with the exception of zip4 and zip8. Results from in situ hybridization revealed that several zip transporters exhibited distinct spatial distribution (e.g., zip8 in the intestinal tract, zip14 in the pronephric tubules). Overall, our findings suggested that exposure to sublethal concentrations of Zn disrupts the homeostasis of essential metals during early development and that different ZIP transporters may play unique roles in regulating Zn homeostasis in various organs in developing zebrafish.


Assuntos
Proteínas de Transporte de Cátions/genética , Homeostase/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Proteínas de Peixe-Zebra/genética , Peixe-Zebra , Zinco/toxicidade , Animais , Cálcio/metabolismo , Cobre/metabolismo , Relação Dose-Resposta a Droga , Larva/efeitos dos fármacos , Larva/metabolismo , Nível de Efeito Adverso não Observado , Poluentes Químicos da Água/metabolismo , Peixe-Zebra/fisiologia , Zinco/metabolismo
10.
Aquat Toxicol ; 225: 105525, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32629302

RESUMO

Halogenated dipeptides, 3, 5-di-I-tyrosylalanine (DIYA), have been identified as novel disinfection byproducts (DBPs), following chloramination of authentic water. However, little is known about their toxicity. Zebrafish embryos were used to assess the toxicity of novel iodinated DBPs (I-DBPs). Although DIYA did not exhibit high acute toxicity to embryonic zebrafish (LC50 > 2 mM), it significantly inhibited pigmentation of melanophores and xanthophores on head, trunk and tail at 500 µM as determined by photographic analysis. Whereas N-phenylthiourea (PTU) as a pigment inhibitor did not inhibit development of yellow pigments. Colorimetric detection of melanin further confirmed these results. Quantitative real time polymerase chain reaction (qRT-PCR) measurements indicated that genes (dct, slc24a5, tyr, tyrp1a, tyrp1b, silva) associated with the melanogenesis pathway were dramatically down-regulated following exposure to 500 µM DIYA. In addition, enzymatic activity of tyrosinase (TYR) decreased, also demonstrating that the underlying mechanism of hypopigmentation was attributed to the disruption of melanogenesis pathway. Transcription levels of xanthophore genes (gch2, bnc2, csf1a, csf1b, pax7a and pax7b) were also monitored by qRT-PCR assay. DIYA exposure up-regulated expression of gch2 and bnc2, but not csf1 and pax7. Tested DIYA analogues, brominated tyrosine was unlikely to inhibit pigmentation, indicating that the iodine substitution and dipeptides structure are of important structural feature for the inhibition of pigmentation. In this study, we observed that DIYA inhibited melanogenesis related genes, which might contribute to pigmentation defects. Moreover, as an emerging I-DBPs, the developmental toxicity of aromatic dipeptides should be further studied.


Assuntos
Dipeptídeos/toxicidade , Desinfetantes/toxicidade , Embrião não Mamífero/efeitos dos fármacos , Hipopigmentação/induzido quimicamente , Poluentes Químicos da Água/toxicidade , Peixe-Zebra/metabolismo , Animais , Embrião não Mamífero/metabolismo , Expressão Gênica/efeitos dos fármacos , Halogenação , Hipopigmentação/genética , Melanóforos/efeitos dos fármacos , Melanóforos/metabolismo , Purificação da Água , Proteínas de Peixe-Zebra/genética
11.
PLoS Biol ; 18(7): e3000561, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32702011

RESUMO

Maternal ß-catenin activity is essential and critical for dorsal induction and its dorsal activation has been thoroughly studied. However, how the maternal ß-catenin activity is suppressed in the nondorsal cells remains poorly understood. Nanog is known to play a central role for maintenance of the pluripotency and maternal -zygotic transition (MZT). Here, we reveal a novel role of Nanog as a strong repressor of maternal ß-catenin signaling to safeguard the embryo against hyperactivation of maternal ß-catenin activity and hyperdorsalization. In zebrafish, knockdown of nanog at different levels led to either posteriorization or dorsalization, mimicking zygotic or maternal activation of Wnt/ß-catenin activities, and the maternal zygotic mutant of nanog (MZnanog) showed strong activation of maternal ß-catenin activity and hyperdorsalization. Although a constitutive activator-type Nanog (Vp16-Nanog, lacking the N terminal) perfectly rescued the MZT defects of MZnanog, it did not rescue the phenotypes resulting from ß-catenin signaling activation. Mechanistically, the N terminal of Nanog directly interacts with T-cell factor (TCF) and interferes with the binding of ß-catenin to TCF, thereby attenuating the transcriptional activity of ß-catenin. Therefore, our study establishes a novel role for Nanog in repressing maternal ß-catenin activity and demonstrates a transcriptional switch between ß-catenin/TCF and Nanog/TCF complexes, which safeguards the embryo from global activation of maternal ß-catenin activity.


Assuntos
Desenvolvimento Embrionário/genética , Proteína Homeobox Nanog/metabolismo , Transativadores/metabolismo , Proteínas de Peixe-Zebra/metabolismo , Peixe-Zebra/embriologia , Peixe-Zebra/genética , beta Catenina/metabolismo , Animais , Padronização Corporal/genética , Núcleo Celular/metabolismo , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Técnicas de Silenciamento de Genes , Masculino , Mutação/genética , Proteína Homeobox Nanog/química , Proteína Homeobox Nanog/genética , Ligação Proteica , Transporte Proteico , Proteínas Repressoras/metabolismo , Transcrição Genética , Via de Sinalização Wnt/genética , Proteínas de Peixe-Zebra/química , Proteínas de Peixe-Zebra/genética , Zigoto/metabolismo
12.
Proc Natl Acad Sci U S A ; 117(27): 15799-15808, 2020 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-32571908

RESUMO

The transcriptome of eukaryotic cells is constantly monitored for errors to avoid the production of undesired protein variants. The evolutionarily conserved nonsense-mediated mRNA decay (NMD) pathway degrades aberrant mRNAs, but also functions in the regulation of transcript abundance in response to changed physiological states. Here, we describe a zebrafish mutant of upf1, encoding the central component of the NMD machinery. Fish homozygous for the upf1 t20450 allele (Y163X) survive until day 10 after fertilization, presenting with impaired T cell development as one of the most conspicuous features of the mutant phenotype. Analysis of differentially expressed genes identified dysregulation of the pre-mRNA splicing pathway, accompanied by perturbed autoregulation of canonical splicing activators (SRSF) and repressors (HNRNP). In upf1-deficient mutants, NMD-susceptible transcripts of ribosomal proteins that are known for their role as noncanonical splicing regulators were greatly increased, most notably, rpl10a When the levels of NMD-susceptible rpl10a transcripts were artificially increased in zebrafish larvae, T cell development was significantly impaired, suggesting that perturbed autoregulation of rpl10a splicing contributes to failing T cell development in upf1 deficiency. Our results identify an extraribosomal tissue-specific function to rpl10a in the immune system, and thus exemplify the advantages of the zebrafish model to study the effects of upf1-deficiency in the context of a vertebrate organism.


Assuntos
Glutationa/análogos & derivados , Degradação do RNAm Mediada por Códon sem Sentido/genética , Processamento de RNA/genética , Proteínas de Ligação a RNA/genética , Linfócitos T/imunologia , Proteínas de Peixe-Zebra/genética , Animais , Códon sem Sentido/genética , Fertilização/genética , Regulação da Expressão Gênica no Desenvolvimento/genética , Glutationa/genética , Homozigoto , Humanos , Degradação do RNAm Mediada por Códon sem Sentido/imunologia , RNA Mensageiro/genética , Fatores de Transcrição/genética , Transcriptoma/genética , Peixe-Zebra/genética
13.
Proc Natl Acad Sci U S A ; 117(26): 15262-15269, 2020 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-32541022

RESUMO

Thyroid hormone (TH) signaling plays an important role in the regulation of long-wavelength vision in vertebrates. In the retina, thyroid hormone receptor ß (thrb) is required for expression of long-wavelength-sensitive opsin (lws) in red cone photoreceptors, while in retinal pigment epithelium (RPE), TH regulates expression of a cytochrome P450 enzyme, cyp27c1, that converts vitamin A1 into vitamin A2 to produce a red-shifted chromophore. To better understand how TH controls these processes, we analyzed the phenotype of zebrafish with mutations in the three known TH nuclear receptor transcription factors (thraa, thrab, and thrb). We found that no single TH nuclear receptor is required for TH-mediated induction of cyp27c1 but that deletion of all three (thraa -/- ;thrab -/- ;thrb -/- ) completely abrogates its induction and the resulting conversion of A1- to A2-based retinoids. In the retina, loss of thrb resulted in an absence of red cones at both larval and adult stages without disruption of the underlying cone mosaic. RNA-sequencing analysis revealed significant down-regulation of only five genes in adult thrb -/- retina, of which three (lws1, lws2, and miR-726) occur in a single syntenic cluster. In the thrb -/- retina, retinal progenitors destined to become red cones were transfated into ultraviolet (UV) cones and horizontal cells. Taken together, our findings demonstrate cooperative regulation of cyp27c1 by TH receptors and a requirement for thrb in red cone fate determination. Thus, TH signaling coordinately regulates both spectral sensitivity and sensory plasticity.


Assuntos
Visão de Cores/fisiologia , Sistema Enzimático do Citocromo P-450/metabolismo , Opsinas/metabolismo , Receptores dos Hormônios Tireóideos/fisiologia , Percepção Visual/fisiologia , Proteínas de Peixe-Zebra/metabolismo , Animais , Visão de Cores/genética , Sistema Enzimático do Citocromo P-450/genética , Deleção de Genes , Regulação da Expressão Gênica , Opsinas/genética , Células Fotorreceptoras Retinianas Cones , Raios Ultravioleta , Peixe-Zebra , Proteínas de Peixe-Zebra/genética
14.
PLoS Genet ; 16(6): e1008869, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32569302

RESUMO

We investigate mutations in trß2, a splice variant of thrb, identifying changes in function, structure, and behavior in larval and adult zebrafish retinas. Two N-terminus CRISPR mutants were identified. The first is a 6BP+1 insertion deletion frameshift resulting in a truncated protein. The second is a 3BP in frame deletion with intact binding domains. ERG recordings of isolated cone signals showed that the 6BP+1 mutants did not respond to red wavelengths of light while the 3BP mutants did respond. 6BP+1 mutants lacked optomotor and optokinetic responses to red/black and green/black contrasts. Both larval and adult 6BP+1 mutants exhibit a loss of red-cone contribution to the ERG and an increase in UV-cone contribution. Transgenic reporters show loss of cone trß2 activation in the 6BP+1 mutant but increase in the density of cones with active blue, green, and UV opsin genes. Antibody reactivity for red-cone LWS1 and LWS2 opsin was absent in the 6BP+1 mutant, as was reactivity for arrestin3a. Our results confirm a critical role for trß2 in long-wavelength cone development.


Assuntos
Visão de Cores/genética , Regulação da Expressão Gênica no Desenvolvimento , Genes erbA/genética , Retina/crescimento & desenvolvimento , Receptores beta dos Hormônios Tireóideos/genética , Animais , Animais Geneticamente Modificados , Diferenciação Celular/genética , Opsinas dos Cones/genética , Opsinas dos Cones/metabolismo , Mutação da Fase de Leitura , Mutação INDEL , Larva , Modelos Animais , Células Fotorreceptoras de Invertebrados/patologia , Retina/citologia , Retina/patologia , Deleção de Sequência , Transativadores/genética , Transativadores/metabolismo , Peixe-Zebra/genética , Peixe-Zebra/crescimento & desenvolvimento , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
15.
Proc Natl Acad Sci U S A ; 117(26): 15066-15074, 2020 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-32554492

RESUMO

Cancer incidence increases exponentially with age when human telomeres are shorter. Similarly, telomerase reverse transcriptase (tert) mutant zebrafish have premature short telomeres and anticipate cancer incidence to younger ages. However, because short telomeres constitute a road block to cell proliferation, telomere shortening is currently viewed as a tumor suppressor mechanism and should protect from cancer. This conundrum is not fully understood. In our current study, we report that telomere shortening promotes cancer in a noncell autonomous manner. Using zebrafish chimeras, we show increased incidence of invasive melanoma when wild-type (WT) tumors are generated in tert mutant zebrafish. Tissues adjacent to melanoma lesions (skin) and distant organs (intestine) in tert mutants exhibited higher levels of senescence and inflammation. In addition, we transferred second generation (G2) tert blastula cells into WT to produce embryo chimeras. Cells with very short telomeres induced increased tumor necrosis factor1-α (TNF1-α) expression and senescence in larval tissues in a noncell autonomous manner, creating an inflammatory environment. Considering that inflammation is protumorigenic, we transplanted melanoma-derived cells into G2 tert zebrafish embryos and observed that tissue environment with short telomeres leads to increased tumor development. To test if inflammation was necessary for this effect, we treated melanoma transplants with nonsteroid anti-inflammatory drugs and show that higher melanoma dissemination can be averted. Thus, apart from the cell autonomous role of short telomeres in contributing to genome instability, we propose that telomere shortening with age causes systemic chronic inflammation leading to increased tumor incidence.


Assuntos
Melanoma/metabolismo , Telômero/metabolismo , Peixe-Zebra/metabolismo , Animais , Modelos Animais de Doenças , Humanos , Melanoma/genética , Melanoma/imunologia , Telomerase/genética , Telomerase/metabolismo , Telômero/genética , Encurtamento do Telômero , Fator de Necrose Tumoral alfa/genética , Fator de Necrose Tumoral alfa/imunologia , Peixe-Zebra/genética , Peixe-Zebra/imunologia , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
16.
Nat Commun ; 11(1): 2797, 2020 06 03.
Artigo em Inglês | MEDLINE | ID: mdl-32493999

RESUMO

Fat distribution is an independent cardiometabolic risk factor. However, its molecular and cellular underpinnings remain obscure. Here we demonstrate that two independent GWAS signals at RSPO3, which are associated with increased body mass index-adjusted waist-to-hip ratio, act to specifically increase RSPO3 expression in subcutaneous adipocytes. These variants are also associated with reduced lower-body fat, enlarged gluteal adipocytes and insulin resistance. Based on human cellular studies RSPO3 may limit gluteofemoral adipose tissue (AT) expansion by suppressing adipogenesis and increasing gluteal adipocyte susceptibility to apoptosis. RSPO3 may also promote upper-body fat distribution by stimulating abdominal adipose progenitor (AP) proliferation. The distinct biological responses elicited by RSPO3 in abdominal versus gluteal APs in vitro are associated with differential changes in WNT signalling. Zebrafish carrying a nonsense rspo3 mutation display altered fat distribution. Our study identifies RSPO3 as an important determinant of peripheral AT storage capacity.


Assuntos
Adipócitos/citologia , Adipócitos/metabolismo , Distribuição da Gordura Corporal , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Trombospondinas/metabolismo , Proteínas de Peixe-Zebra/metabolismo , Adipócitos/efeitos dos fármacos , Tecido Adiposo/metabolismo , Adiposidade/genética , Adulto , Alelos , Animais , Biomarcadores/metabolismo , Diferenciação Celular/efeitos dos fármacos , Linhagem Celular , Tamanho Celular/efeitos dos fármacos , Doxiciclina/farmacologia , Feminino , Regulação da Expressão Gênica/efeitos dos fármacos , Glucose/metabolismo , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Masculino , Pessoa de Meia-Idade , Mutação/genética , Polimorfismo de Nucleotídeo Único/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Caracteres Sexuais , Células-Tronco/metabolismo , Trombospondinas/genética , Relação Cintura-Quadril , Via de Sinalização Wnt/efeitos dos fármacos , Peixe-Zebra/genética , Proteínas de Peixe-Zebra/genética
17.
PLoS Genet ; 16(6): e1008841, 2020 06.
Artigo em Inglês | MEDLINE | ID: mdl-32544203

RESUMO

Hypomyelination, a neurological condition characterized by decreased production of myelin sheets by glial cells, often has no known etiology. Elucidating the genetic causes of hypomyelination provides a better understanding of myelination, as well as means to diagnose, council, and treat patients. Here, we present evidence that YIPPEE LIKE 3 (YPEL3), a gene whose developmental role was previously unknown, is required for central and peripheral glial cell development. We identified a child with a constellation of clinical features including cerebral hypomyelination, abnormal peripheral nerve conduction, hypotonia, areflexia, and hypertrophic peripheral nerves. Exome and genome sequencing revealed a de novo mutation that creates a frameshift in the open reading frame of YPEL3, leading to an early stop codon. We used zebrafish as a model system to validate that YPEL3 mutations are causative of neuropathy. We found that ypel3 is expressed in the zebrafish central and peripheral nervous system. Using CRISPR/Cas9 technology, we created zebrafish mutants carrying a genomic lesion similar to that of the patient. Our analysis revealed that Ypel3 is required for development of oligodendrocyte precursor cells, timely exit of the perineurial glial precursors from the central nervous system (CNS), formation of the perineurium, and Schwann cell maturation. Consistent with these observations, zebrafish ypel3 mutants have metabolomic signatures characteristic of oligodendrocyte and Schwann cell differentiation defects, show decreased levels of Myelin basic protein in the central and peripheral nervous system, and develop defasciculated peripheral nerves. Locomotion defects were observed in adult zebrafish ypel3 mutants. These studies demonstrate that Ypel3 is a novel gene required for perineurial cell development and glial myelination.


Assuntos
Regulação da Expressão Gênica no Desenvolvimento , Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central/genética , Bainha de Mielina/patologia , Neurogênese/genética , Proteínas Supressoras de Tumor/genética , Animais , Plexo Braquial/diagnóstico por imagem , Criança , Análise Mutacional de DNA , Modelos Animais de Doenças , Embrião não Mamífero , Feminino , Mutação da Fase de Leitura , Substância Cinzenta/diagnóstico por imagem , Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central/diagnóstico por imagem , Doenças Desmielinizantes Hereditárias do Sistema Nervoso Central/patologia , Humanos , Imagem por Ressonância Magnética , Neuroglia/patologia , Oligodendroglia , Nervo Isquiático/diagnóstico por imagem , Substância Branca/diagnóstico por imagem , Sequenciamento Completo do Exoma , Peixe-Zebra , Proteínas de Peixe-Zebra/genética
18.
Toxicol Lett ; 331: 143-151, 2020 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-32525014

RESUMO

Although organotin compounds are known to disturb thyroid signaling and antioxidant defense system, the sex-differences underlying these effects of triphenyltin chloride (TPT) in fish remain unclear. To understand these differences, adult zebrafish (Danio rerio) were exposed to different concentrations of TPT (0, 10, 100, or 1000 ng/L) for 28 days. Female zebrafish exposed to TPT showed significantly increased thyroxine (T4) content and decrease triiodothyronine (T3) content, possibly due to downregulation of deiodinase (dio2) and uridine diphosphate glucuronosyl transferase (ugt1ab). However, decreased T4 and T3 contents in male zebrafish accompanied with upregulation of dio1, dio2 and ugt1ab. TPT exposure can lead to sex-specific thyroid disruption in adult zebrafish via alterations the Hypothalamus-pituitary-thyroid-liver axis. In addition, the gene expression levels of metabolizing enzymes, such as cyp1b, cyp1c, gpx1a, or sult1st1 were also to vary in a sex-dependent manner in adult zebrafish liver. Downregulation of cyp19a and cyp19b and decreased 17ß-estradiol (E2) contents were detected in both female and male zebrafish. Therefore, a sex-specific of thyroid disruption response after TPT exposure was observed in adult zebrafish, possibly due to inherent in female or males detoxifying enzyme capacities.


Assuntos
Disruptores Endócrinos/toxicidade , Compostos Orgânicos de Estanho/toxicidade , Caracteres Sexuais , Glândula Tireoide/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Proteínas de Peixe-Zebra , Peixe-Zebra/metabolismo , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/enzimologia , Relação Dose-Resposta a Droga , Feminino , Expressão Gênica/efeitos dos fármacos , Fígado/efeitos dos fármacos , Fígado/enzimologia , Masculino , Glândula Tireoide/metabolismo , Hormônios Tireóideos/genética , Hormônios Tireóideos/metabolismo , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo
19.
PLoS One ; 15(6): e0232308, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32530962

RESUMO

Zebrafish have the ability to regenerate damaged cells and tissues by activating quiescent stem and progenitor cells or reprogramming differentiated cells into regeneration-competent precursors. Proliferation among the cells that will functionally restore injured tissues is a fundamental biological process underlying regeneration. Midkine-a is a cytokine growth factor, whose expression is strongly induced by injury in a variety of tissues across a range of vertebrate classes. Using a zebrafish Midkine-a loss of function mutant, we evaluated regeneration of caudal fin, extraocular muscle and retinal neurons to investigate the function of Midkine-a during epimorphic regeneration. In wildtype zebrafish, injury among these tissues induces robust proliferation and rapid regeneration. In Midkine-a mutants, the initial proliferation in each of these tissues is significantly diminished or absent. Regeneration of the caudal fin and extraocular muscle is delayed; regeneration of the retina is nearly completely absent. These data demonstrate that Midkine-a is universally required in the signaling pathways that convert tissue injury into the initial burst of cell proliferation. Further, these data highlight differences in the molecular mechanisms that regulate epimorphic regeneration in zebrafish.


Assuntos
Midkina/metabolismo , Regeneração/fisiologia , Proteínas de Peixe-Zebra/metabolismo , Peixe-Zebra/metabolismo , Nadadeiras de Animais/fisiologia , Animais , Animais Geneticamente Modificados/metabolismo , Diferenciação Celular , Proliferação de Células , Midkina/genética , Mutagênese , Neuroglia/citologia , Neuroglia/metabolismo , Músculos Oculomotores/fisiologia , Neurônios Retinianos/fisiologia , Proteínas de Peixe-Zebra/genética
20.
Nat Commun ; 11(1): 2984, 2020 06 12.
Artigo em Inglês | MEDLINE | ID: mdl-32533114

RESUMO

ADNP (Activity Dependent Neuroprotective Protein) is a neuroprotective protein whose aberrant expression has been frequently linked to neural developmental disorders, including the Helsmoortel-Van der Aa syndrome (also called the ADNP syndrome). However, its role in neural development and pathology remains unclear. Here, we show that ADNP is required for neural induction and differentiation by enhancing Wnt signaling. Mechanistically, ADNP functions to stabilize ß-Catenin through binding to its armadillo domain which prevents its association with key components of the degradation complex: Axin and APC. Loss of ADNP promotes the formation of the degradation complex and ß-Catenin degradation via ubiquitin-proteasome pathway, resulting in down-regulation of key neuroectoderm developmental genes. In addition, adnp gene disruption in zebrafish leads to defective neurogenesis and reduced Wnt signaling. Our work provides important insights into the role of ADNP in neural development and the pathology of the Helsmoortel-Van der Aa syndrome caused by ADNP gene mutation.


Assuntos
Diferenciação Celular/genética , Proteínas de Homeodomínio/genética , Células-Tronco Embrionárias Murinas/metabolismo , Proteínas do Tecido Nervoso/genética , Neurônios/metabolismo , Via de Sinalização Wnt/genética , beta Catenina/genética , Animais , Células Cultivadas , Regulação da Expressão Gênica no Desenvolvimento , Células HEK293 , Proteínas de Homeodomínio/metabolismo , Humanos , Hibridização In Situ/métodos , Camundongos , Camundongos Knockout , Células-Tronco Embrionárias Murinas/citologia , Mutação , Proteínas do Tecido Nervoso/metabolismo , Neurônios/citologia , Ligação Proteica , Peixe-Zebra/embriologia , Peixe-Zebra/genética , Peixe-Zebra/metabolismo , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo , beta Catenina/metabolismo
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