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1.
Neurobiol Learn Mem ; 179: 107402, 2021 03.
Artigo em Inglês | MEDLINE | ID: mdl-33581316

RESUMO

The insular cortex (IC) is notably implicated in emotional and cognitive processing; however, little is known regarding to what extent its two main subregions play functionally distinct roles on memory consolidation of conditioned fear tasks. Here we verified the effects of temporary functional inactivation of the anterior (aIC) and posterior IC (pIC) on contextual and tone fear memory. Rats received post-training bilateral infusions of the GABAA receptor agonist muscimol into either the aIC or pIC and were tested 48 and 72 h after the delay tone fear conditioning session to assess the background contextual (CFC) and tone (TFC) fear conditioning, respectively. Inactivation of the aIC during memory consolidation did not affect fear memory for CFC or TFC. On the other hand, post-training inactivation of the pIC impaired TFC but not CFC. Our findings indicate that the pIC is a necessary part of the neural circuitry related to the consolidation of cued-fear memories.


Assuntos
Córtex Cerebral/fisiologia , Condicionamento Clássico/fisiologia , Medo , Consolidação da Memória/fisiologia , Estimulação Acústica , Animais , Córtex Cerebral/efeitos dos fármacos , Condicionamento Clássico/efeitos dos fármacos , Agonistas de Receptores de GABA-A/farmacologia , Consolidação da Memória/efeitos dos fármacos , Muscimol/farmacologia , Ratos
2.
Braz. j. med. biol. res ; 48(11): 965-972, Nov. 2015. tab, graf
Artigo em Inglês | LILACS | ID: lil-762902

RESUMO

This study reviewed the use of the Strengths and Weaknesses of Attention-Deficit/Hyperactivity-symptoms and Normal-behaviors (SWAN) rating scale in diagnostic and evolutive approaches to attention deficit hyperactivity disorder (ADHD) and in correlational studies of the disorder. A review of articles published in indexed journals from electronic databases was conducted and 61 articles on the SWAN scale were analyzed. From these, 27 were selected to a) examine use of SWAN in research on attention disorders and b) verify evidence of its usefulness in the areas of genetics, neuropsychology, diagnostics, psychiatric comorbidities, neuroimaging, pharmacotherapy, and to examine its statistical reliability and validity in studies of diverse populations. This review of articles indicated a growing use of the SWAN scale for diagnostic purposes, for therapy, and in research on areas other than ADHD, especially when compared with other reliable scales. Use of the scale in ADHD diagnosis requires further statistical testing to define its psychometric properties.


Assuntos
Humanos , Transtorno do Deficit de Atenção com Hiperatividade/diagnóstico , Escala de Avaliação Comportamental/normas , Avaliação de Sintomas/métodos , Transtorno do Deficit de Atenção com Hiperatividade/epidemiologia , Transtorno do Deficit de Atenção com Hiperatividade/genética , Escala de Avaliação Comportamental/estatística & dados numéricos , Comorbidade , Reprodutibilidade dos Testes , Inquéritos e Questionários , Estudos de Validação como Assunto
3.
Braz J Med Biol Res ; 48(11): 965-72, 2015 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-26313140

RESUMO

This study reviewed the use of the Strengths and Weaknesses of Attention-Deficit/Hyperactivity-symptoms and Normal-behaviors (SWAN) rating scale in diagnostic and evolutive approaches to attention deficit hyperactivity disorder (ADHD) and in correlational studies of the disorder. A review of articles published in indexed journals from electronic databases was conducted and 61 articles on the SWAN scale were analyzed. From these, 27 were selected to a) examine use of SWAN in research on attention disorders and b) verify evidence of its usefulness in the areas of genetics, neuropsychology, diagnostics, psychiatric comorbidities, neuroimaging, pharmacotherapy, and to examine its statistical reliability and validity in studies of diverse populations. This review of articles indicated a growing use of the SWAN scale for diagnostic purposes, for therapy, and in research on areas other than ADHD, especially when compared with other reliable scales. Use of the scale in ADHD diagnosis requires further statistical testing to define its psychometric properties.


Assuntos
Transtorno do Deficit de Atenção com Hiperatividade/diagnóstico , Escala de Avaliação Comportamental/normas , Avaliação de Sintomas/métodos , Transtorno do Deficit de Atenção com Hiperatividade/epidemiologia , Transtorno do Deficit de Atenção com Hiperatividade/genética , Escala de Avaliação Comportamental/estatística & dados numéricos , Comorbidade , Humanos , Reprodutibilidade dos Testes , Inquéritos e Questionários , Estudos de Validação como Assunto
4.
Photochem Photobiol Sci ; 14(2): 320-8, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25373732

RESUMO

Lophine and four of its derivatives were used as activators (ACTs) of the chemiluminescent peroxyoxalate (PO) reaction of bis(2,4,6-trichlorophenyl)oxalate with H2O2, catalysed by imidazole. Kinetic emission assays have shown that with the tested compounds the reaction mechanism, regarding the formation of the high energy intermediate (HEI) of the PO reaction, occurs as previously seen for commonly used ACTs. A bimolecular interaction of the compounds with the HEI leads to chemiexcitation through the chemically initiated electron exchange luminescence (CIEEL) mechanism, as confirmed by a linear free-energy correlation between the relative catalytic rate constants and the oxidation potentials of the compounds. The yields of excited state formation and light emission, in the range of 10(-2)-10(-3) E mol(-1), are comparable to the ones seen with commonly used ACTs. A Hammett plot with ρ = -0.90 indicates the buildup of a partial positive charge on the transition step of the catalytic process, consistent with the formation of a radical cation of the ACT, being an additional validation of the CIEEL mechanism in this system.

5.
Paediatr Int Child Health ; 33(2): 102-7, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23925284

RESUMO

BACKGROUND: Rotavirus is an important aetiological agent for severe diarrhoea in infants and young children worldwide. Anti-rotavirus antibodies in human colostrum and milk may interfere with rotavirus vaccination seroconversion. AIMS: To verify the presence of anti-rotavirus secretory IgA antibodies (SIgA) and the neutralizing capacity of 30 colostrum and 30 milk samples from Brazilian women in two different centres and analyze their persistence throughout lactation. METHODS: Colostrum and milk samples from healthy nursing mothers were tested for the presence of anti-rotavirus SIgA using conventional ELISA and their capacity to neutralize rotavirus using MA-104 cell cultures. Total IgA concentrations and anti-rotavirus SIgA levels were measured in samples collected from three mothers during 90 or 240 days of the lactation period. RESULTS: Colostrum samples showed higher levels of anti-rotavirus SIgA and higher neutralizing ability than in milk. However, these antibodies levels were not statistically different. In addition, there was no correlation between antibody levels and the neutralizing activity observed in colostrum and milk samples. Follow-up of three mothers demonstrated the persistence of anti-rotavirus and total IgA levels throughout lactation. CONCLUSIONS: These results support the encouragement of breastfeeding as a mechanism of protection against rotavirus infection in lactating infants. Components other than SIgA antibodies might play an important role in virus neutralization.


Assuntos
Anticorpos Neutralizantes/imunologia , Anticorpos Antivirais/imunologia , Antígenos Virais/imunologia , Colostro/imunologia , Imunoglobulina A Secretora/imunologia , Leite Humano/imunologia , Rotavirus/imunologia , Anticorpos Neutralizantes/análise , Anticorpos Antivirais/análise , Brasil , Ensaio de Imunoadsorção Enzimática , Feminino , Humanos , Imunoglobulina A Secretora/análise , Testes de Neutralização
6.
Epidemiol Infect ; 141(1): 181-7, 2013 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-22417705

RESUMO

This study aimed to determine the prevalence of serological markers for HIV-1/2, HBV, HCV, Treponema cruzi and T. pallidum infections. The association of these infections with risk factors in a population from Salvador, Bahia, Brazil was also analysed. Of the 780 enrolled individuals, 545 (70%) were female and 235 (30%) were male. Seroprevalence of 0·8% (6/702), 1·3% (9/678), 1·5% (10/684), 3·5% (23/663) and 11·5% (77/668) for HIV-1/2, HBV, HCV, T. cruzi and T. pallidum infections, respectively, was observed. The seroprevalence of T. pallidum was higher in males 20% (43/210) than in females 7% (34/458) (P < 0·01). An association between age and seroprevalence for T. cruzi (P = 0·02) and T. pallidum (P < 0·01) was observed. HBsAg was associated with having tattoos (3/37 vs. 6/623, P = 0·01) and not having a steady sexual partner (5/141 vs. 4/473, P = 0·04), while anti-HIV-1/2 was associated with having tattoos (2/39 vs. 4/647, P = 0·04); however, larger studies are needed to categorically state the relationship of these risk factors with infectious agents. The prevalence of serological markers for HIV-1/2, HBV, HCV and T. cruzi was consistent with other studies.


Assuntos
Patógenos Transmitidos pelo Sangue/isolamento & purificação , Infecções por HIV/epidemiologia , Hepatite B/epidemiologia , Hepatite C/epidemiologia , Infecções por Treponema/epidemiologia , Adolescente , Adulto , Fatores Etários , Idoso , Idoso de 80 Anos ou mais , Brasil/epidemiologia , Criança , Pré-Escolar , Estudos Transversais , Feminino , Humanos , Lactente , Recém-Nascido , Masculino , Pessoa de Meia-Idade , Prevalência , Fatores de Risco , Estudos Soroepidemiológicos , Comportamento Sexual , Tatuagem/efeitos adversos , Infecções por Treponema/microbiologia , Adulto Jovem
7.
Gene Expr Patterns ; 10(6): 251-8, 2010 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-20566374

RESUMO

The Wnts are a highly conserved family of secreted glycoproteins involved in cell-cell signaling and pattern formation during early embryonic development. Teasing out the role of individual Wnt molecules through development is challenging. Gene duplications are one of the most important mechanisms for generating evolutionary variations. The current consensus suggests that most anatomical variation is generated by divergence of regulatory control regions rather than by coding sequence divergence. Thus phylogenetic comparisons of divergent gene expression patterns are essential to understanding ancestral morphogenetic patterns from which subsequent anatomy diversified in modern lineages. We previously demonstrated strongest expression of zebrafish wnt9b within its heart tube, limb bud and ventral/anterior ectoderm during oral and pharyngeal arch patterning. Our goal is to compare and contrast zwnt9b to its closest paralog, zwnt9a. Sequenced, fulllength zebrafish wnt9a and wnt9b cDNA clones were used for phylogenetic analysis, which suggests their derivation from a common pre-vertebrate archeolog by gene duplication and divergence. Here we demonstrate that zwnt9a expression is found within unique (CNS, pronephric ducts, sensory organs) and overlapping (pectoral fin buds) expression domains relative to zwnt9b. Apparently, Wnt9 paralogs differentially parsed common ancestral expression domains during their subsequent rounds of gene duplication, divergence and loss in different vertebrate lineages. This expression data suggests ancestral roles for Wnt9s in early patterning of neural/oral-pharyngeal ectoderm and mesendoderm derivatives.


Assuntos
Região Branquial/embriologia , Boca/embriologia , Sistema Nervoso/embriologia , Proteínas Wnt/genética , Proteínas de Peixe-Zebra/genética , Peixe-Zebra/embriologia , Peixe-Zebra/genética , Sequência de Aminoácidos , Animais , Região Branquial/metabolismo , Clonagem Molecular , Ectoderma/embriologia , Ectoderma/metabolismo , Embrião não Mamífero , Endoderma/embriologia , Endoderma/metabolismo , Evolução Molecular , Regulação da Expressão Gênica no Desenvolvimento , Dados de Sequência Molecular , Boca/metabolismo , Sistema Nervoso/metabolismo , Filogenia , Homologia de Sequência , Proteínas Wnt/fisiologia , Proteínas de Peixe-Zebra/fisiologia
8.
Protein Pept Lett ; 16(8): 877-86, 2009.
Artigo em Inglês | MEDLINE | ID: mdl-19689413

RESUMO

Many snake venom phospholipase A(2)s (vPLA(2)s) present biological effects that are independent of hydrolytic activity. Here we review the evidence for the calcium-independent membrane damaging activity of vPLA(2)s, the possible relevance of this activity on their biological effects, and models for the mechanism of membrane permeabilization by these proteins.


Assuntos
Fosfolipases A2/metabolismo , Venenos de Serpentes/enzimologia , Serpentes , Animais , Membrana Celular/metabolismo , Permeabilidade da Membrana Celular , Humanos , Mutagênese Sítio-Dirigida , Fosfolipases A2/química , Fosfolipases A2/genética
9.
Dev Dyn ; 238(6): 1605-12, 2009 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-19418442

RESUMO

Mutations in human TBX22 cause X-linked cleft palate with ankyloglossia syndrome (CPX; OMIM 303400). Since the secondary palate was an adaptation to breathing on land, we characterized zebrafish tbx22 to study molecular mechanisms regulating early vertebrate craniofacial patterning. Rapid Amplification of cDNA Ends (RACE) analyses revealed two zebrafish tbx22 splice isoforms, tbx22-1 and tbx22-2, encoding proteins of 444 and 400 amino acids, respectively. tbx22-1 resembles canonical Tbx22 orthologs, while tbx22-2 lacks conserved N-terminal sequence. Developmental RT-PCR revealed that tbx22-1 is maternally and zygotically expressed, while tbx22-2 is expressed zygotically. WISH analyses revealed strong tbx22 mRNA expression in ectomesenchyme underlying the stomodeum, a bilaminar epithelial structure demarcating early mouth formation, and in early presumptive jaw joints. Zebrafish tbx22 expression mirrored some aspects of mammalian Tbx22, consistent with roles in early vertebrate face patterning. These studies identify an early transcription factor governing vertebrate facial development, which may underlie common craniofacial birth disorders. Developmental Dynamics 238:1605-1612, 2009. (c) 2009 Wiley-Liss, Inc.


Assuntos
Processamento Alternativo , Ossos Faciais/embriologia , Crânio/embriologia , Proteínas com Domínio T/genética , Proteínas com Domínio T/metabolismo , Proteínas de Peixe-Zebra/genética , Proteínas de Peixe-Zebra/metabolismo , Peixe-Zebra/genética , Sequência de Aminoácidos , Animais , Sequência de Bases , Padronização Corporal/genética , Anormalidades Craniofaciais/genética , Ossos Faciais/anatomia & histologia , Ossos Faciais/fisiologia , Regulação da Expressão Gênica no Desenvolvimento , Humanos , Dados de Sequência Molecular , Filogenia , Isoformas de Proteínas/genética , Isoformas de Proteínas/metabolismo , Alinhamento de Sequência , Crânio/anatomia & histologia , Crânio/fisiologia , Proteínas com Domínio T/química , Proteínas com Domínio T/classificação , Peixe-Zebra/anatomia & histologia , Peixe-Zebra/embriologia , Peixe-Zebra/fisiologia , Proteínas de Peixe-Zebra/química
10.
Inflamm Res ; 58(4): 210-7, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19169647

RESUMO

OBJECTIVE: Suramin is a polysulphonated napthylurea antiprotozoal and anthelminitic drug, which also presents inhibitory activity against a broad range of enzymes. Here we evaluate the effect of suramin on the hydrolytic and biological activities of secreted human group IIA phospholipase A(2) (hsPLA(2)GIIA). MATERIALS AND METHODS: The hsPLA(2)GIIA was expressed in E. coli, and refolded from inclusion bodies. The hydrolytic activity of the recombinant enzyme was measured using mixed dioleoylphosphatidylcholine/dioleoylphosphatidylglycerol (DOPC/DOPG) liposomes. The activation of macrophage cell line RAW 264.7 by hsPLA(2) GIIA was monitored by NO release, and bactericidal activity against Micrococcus luteus was evaluated by colony counting and by flow cytometry using the fluorescent probe Sytox Green. RESULTS: The hydrolytic activity of the hsPLA(2) GIIA was inhibited by a concentration of 100 nM suramin and the activation of macrophages by hsPLA(2) GIIA was abolished at protein/suramin molar ratios where the hydrolytic activity of the enzyme was inhibited. In contrast, both the bactericidal activity of hsPLA(2) GIIA against Micrococcus luteus and permeabilization of the bacterial inner membrane were unaffected by suramin concentrations up to 50 microM. CONCLUSIONS: These results demonstrate that suramin selectively inhibits the activity of the hsPLA(2) GIIA against macrophages, whilst leaving the anti-bacterial function unchanged.


Assuntos
Antinematódeos/farmacologia , Fosfolipases A2 do Grupo II/metabolismo , Ativação de Macrófagos/efeitos dos fármacos , Suramina/farmacologia , Animais , Antinematódeos/química , Linhagem Celular , Fosfolipases A2 do Grupo II/química , Fosfolipases A2 do Grupo II/genética , Humanos , Corpos de Inclusão/enzimologia , Ativação de Macrófagos/fisiologia , Macrófagos/citologia , Macrófagos/fisiologia , Testes de Sensibilidade Microbiana , Estrutura Molecular , Conformação Proteica , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Suramina/química
11.
Neuroscience ; 153(1): 84-94, 2008 Apr 22.
Artigo em Inglês | MEDLINE | ID: mdl-18367339

RESUMO

The dorsal striatum (DS) is involved in various forms of learning and memory such as procedural learning, habit learning, reward-association and emotional learning. We have previously reported that bilateral DS lesions disrupt tone fear conditioning (TFC), but not contextual fear conditioning (CFC) [Ferreira TL, Moreira KM, Ikeda DC, Bueno OFA, Oliveira MGM (2003) Effects of dorsal striatum lesions in tone fear conditioning and contextual fear conditioning. Brain Res 987:17-24]. To further elucidate the participation of DS in emotional learning, in the present study, we investigated the effects of bilateral pretest (postraining) electrolytic DS lesions on TFC. Given the well-acknowledged role of the amygdala in emotional learning, we also examined a possible cooperation between DS and the amygdala in TFC, by using asymmetrical electrolytic lesions, consisting of a unilateral lesion of the central amygdaloid nucleus (CeA) combined to a contralateral DS lesion. The results show that pre-test bilateral DS lesions disrupt TFC responses, suggesting that DS plays a role in the expression of TFC. More importantly, rats with asymmetrical pre-training lesions were impaired in TFC, but not in CFC tasks. This result was confirmed with muscimol asymmetrical microinjections in DS and CeA, which reversibly inactivate these structures. On the other hand, similar pretest lesions as well as unilateral electrolytic lesions of CeA and DS in the same hemisphere did not affect TFC. Possible anatomical substrates underlying the observed effects are proposed. Overall, the present results underscore that other routes, aside from the well-established CeA projections to the periaqueductal gray, may contribute to the acquisition/consolidation of the freezing response associated to a TFC task. It is suggested that CeA may presumably influence DS processing via a synaptic relay on dopaminergic neurons of the substantia nigra compacta and retrorubral nucleus. The present observations are also in line with other studies showing that TFC and CFC responses are mediated by different anatomical networks.


Assuntos
Tonsila do Cerebelo/fisiologia , Condicionamento Psicológico/fisiologia , Corpo Estriado/fisiologia , Medo/fisiologia , Reação de Congelamento Cataléptica/fisiologia , Rede Nervosa/fisiologia , Tonsila do Cerebelo/anatomia & histologia , Animais , Corpo Estriado/anatomia & histologia , Denervação , Estimulação Elétrica/efeitos adversos , Emoções/fisiologia , Lateralidade Funcional/fisiologia , Agonistas GABAérgicos/farmacologia , Masculino , Rede Nervosa/anatomia & histologia , Vias Neurais/anatomia & histologia , Vias Neurais/fisiologia , Testes Neuropsicológicos , Ratos , Ratos Wistar
12.
Behav Brain Res ; 171(1): 162-9, 2006 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-16677727

RESUMO

Conditioned place preference is an animal model used to evaluate the affective properties of natural rewards and drugs of abuse. This animal model is a kind of classical conditioning that depends on learning and memory. The basolateral amygdala (BLA) plays an important role in the consolidation and extinction of memory for this task. However, there is a lack of evidence demonstrating protein synthesis dependent reconsolidation following retrieval in conditioned animals. In other words, is it possible to observe morphine-associated place preference if recall of this preference is disrupted? Accordingly, we investigated this hypothesis by BLA infusion of protein synthesis inhibitor, anisomycin, immediately after retrieval (test) in conditioned place preference paradigm. In the first experiment, the conditioned animals were exposed to the two sides of the apparatus for 15 min in a drug-free state during retrieval. In the second experiment, the animals received an injection of morphine (7.5 mg/kg, i.p.) and immediately after, they were exposed to the two sides of the apparatus for 15 min. Finally in the third experiment, after habituation and training in the conditioned place preference task, the animals received an injection of the unconditioned stimulus (morphine, i.p.; 7.5 mg/kg) followed by confinement for 10 min in the morphine-paired compartment (conditioned stimulus) during memory retrieval. For the three experiments the animals were subsequently exposed in a free-drug state to the two sides of the apparatus for the retest. Our results show that the protein synthesis inhibition in all of these experimental designs had no effect on conditioned place preference memory under conditions that would initiate reconsolidation, suggesting that if reconsolidation of a conditioned place preference task exists it is not mediated by protein synthesis in basolateral amygdala. The effect of anisomycin on consolidation of contextual fear conditioning was also investigated as a positive control to assure that the negative results were not due to methodological problems. Using the same dose of anisomycin (62.5 microg/1 microl) in morphine-associated place preference procedures, we have found that this anisomycin dose blocks the consolidation of contextual fear memory, ruling out the possibility that these negative results can be attributed to methodological problem of some sort.


Assuntos
Tonsila do Cerebelo/efeitos dos fármacos , Aprendizagem por Associação/efeitos dos fármacos , Condicionamento Clássico/efeitos dos fármacos , Rememoração Mental/efeitos dos fármacos , Morfina/farmacologia , Biossíntese de Proteínas/fisiologia , Tonsila do Cerebelo/metabolismo , Análise de Variância , Animais , Anisomicina/administração & dosagem , Aprendizagem por Associação/fisiologia , Condicionamento Clássico/fisiologia , Meio Ambiente , Masculino , Rememoração Mental/fisiologia , Microinjeções , Entorpecentes/farmacologia , Biossíntese de Proteínas/efeitos dos fármacos , Inibidores da Síntese de Proteínas/administração & dosagem , Ratos , Ratos Endogâmicos WF , Recompensa
13.
J Dent Res ; 84(9): 832-6, 2005 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16109993

RESUMO

Fluoride is an effective agent for the prevention of dental caries. However, the mechanism of how excessive fluoride exposure causes fluorosis remains uncertain. Zebrafish (Danio rerio) exhibit periodic tooth replacement throughout their lives, thereby providing continuous access to teeth at developmental stages susceptible to fluoride exposure. Zebrafish teeth do not contain true enamel, but consist of a hard enameloid surface. Therefore, we asked whether zebrafish could be used as a model organism for the study of dental fluorosis. Scanning electron microscopy of fluoride-treated teeth demonstrated that the enameloid was pitted and rough, and FTIR analysis demonstrated that the teeth also contained a significantly higher organic content when compared with untreated controls. Furthermore, we demonstrate for the first time that decreased expression of an important signaling molecule (Alk8) in tooth development may contribute to the observed fluorotic phenotype, and that increased cell apoptosis may also play a role in the mechanism of fluorosis.


Assuntos
Cariostáticos/toxicidade , Esmalte Dentário/química , Fluoretos/toxicidade , Fluorose Dentária/patologia , Modelos Animais , Peixe-Zebra , Receptores de Ativinas Tipo I/biossíntese , Ameloblastos/patologia , Animais , Cariostáticos/análise , Esmalte Dentário/patologia , Regulação para Baixo , Fluoretos/análise , Fluorose Dentária/metabolismo , Imuno-Histoquímica , Microscopia Eletrônica de Varredura , Espectroscopia de Infravermelho com Transformada de Fourier , Proteínas de Peixe-Zebra/biossíntese
14.
Dev Dyn ; 228(4): 683-96, 2003 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-14648845

RESUMO

The type I TGFbeta family member receptor alk8 acts in bone morphogenetic protein (BMP) signaling pathways to establish dorsoventral patterning in the early zebrafish embryo. Here, we present evidence that alk8 is required for neural crest cell (NCC) formation and that alk8 signaling gradients direct the proper patterning of premigratory NCCs. We extend our previous functional studies of alk8 to demonstrate that ectopic expression of constitutively active and dominant negative Alk8, consistently results in more medially or laterally positioned premigratory NCCs, respectively. We also demonstrate that patterning defects in premigratory NCCs, induced by alk8 misexpression, correlate with subsequent defects in NCC-derived pharyngeal arch cartilages. Furthermore, an anteroposterior effect is revealed, where overexpression of Alk8 more severely affects anterior arch cartilages and decreased Alk8 activity more severely affects posterior arch cartilage formation. Ectopic expression studies of alk8 are supported by analyses of zygotic and maternal-zygotic laf/alk8 mutants and of several BMP pathway mutants. Pharyngeal mesodermal and endodermal defects in laf/alk8 mutants suggest additional roles for alk8 in patterning of these tissues. Our results provide insight into alk8-mediated BMP signaling gradients and the establishment of premigratory NCC mediolateral positioning, and extend the model for BMP patterning of the neural crest to include that of NCC-derived pharyngeal arch cartilages.


Assuntos
Receptores de Ativinas Tipo I/fisiologia , Região Branquial/embriologia , Cartilagem/embriologia , Crista Neural/embriologia , Proteínas de Peixe-Zebra/fisiologia , Azul Alciano/farmacologia , Animais , Apoptose , Padronização Corporal , Cartilagem/metabolismo , Movimento Celular , Corantes/farmacologia , Ectoderma/metabolismo , Embrião não Mamífero/metabolismo , Genes Dominantes , Genótipo , Marcação In Situ das Extremidades Cortadas , Mutação , Crista Neural/citologia , RNA Mensageiro/metabolismo , Rombencéfalo/metabolismo , Transdução de Sinais , Fator de Crescimento Transformador beta/metabolismo , Peixe-Zebra
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