RESUMO
Cell migration is a fundamental phenomenon that underlies tissue morphogenesis, wound healing, immune response, and cancer metastasis. Great progresses have been made in research methodologies, with cell migration identified as a highly orchestrated process. Brain is considered the most complex organ in the human body, containing many types of neural cells with astrocytes playing crucial roles in monitoring normal functions of the central nervous system. Astrocytes are mostly quiescent under normal physiological conditions in the adult brain but become migratory after injury. Under most known pathological conditions in the brain, spinal cord and retina, astrocytes are activated and become hypertrophic, hyperplastic, and up-regulating GFAP based on the grades of severity. These three observations are the hallmark in glia scar formation-astrogliosis. The reactivation process is initiated with structural changes involving cell process migration and ended with cell migration. Detailed mechanisms in astrocyte migration have not been studied extensively and remain largely unknown. Here, we therefore attempt to review the mechanisms in migration of astrocytes.
Assuntos
Astrócitos/metabolismo , Movimento Celular/fisiologia , Animais , Encéfalo/citologia , Encéfalo/metabolismo , Adesão Celular/fisiologia , Células Cultivadas , Humanos , Medula Espinal/citologia , Medula Espinal/metabolismoRESUMO
Gene expression studies are important for revealing gene functions putatively involved in biological processes. We were interested in identifying differentially expressed genes during leaf development in rice. We combined the RNA arbitrarily primed-polymerase chain reaction (RAP-PCR) and dot blot hybridization methods to screen a rice leaf primordium cDNA library. Three developmental stages during vegetative growth were examined. The cDNA clones showing different hybridization patterns were further analyzed and verified. Here we demonstrate that the combination of RAP-PCR and dot blot hybridization could provide an efficient and relatively low-cost cDNA library screening approach to discover genes not previously known to be associated with leaf development in rice. We believe that the findings described here will help to elucidate the molecular mechanism(s) underlying the developmental processes of rice leaf.
Assuntos
Perfilação da Expressão Gênica/economia , Perfilação da Expressão Gênica/métodos , Oryza/crescimento & desenvolvimento , Oryza/genética , Folhas de Planta/genética , Reação em Cadeia da Polimerase/economia , Reação em Cadeia da Polimerase/métodos , Northern Blotting , Regulação da Expressão Gênica no Desenvolvimento , Regulação da Expressão Gênica de Plantas , Genes de Plantas , Folhas de Planta/crescimento & desenvolvimento , RNA de Plantas/genética , RNA de Plantas/metabolismo , Reprodutibilidade dos TestesRESUMO
Our recent findings indicate an induced upregulation of 14-3-3gamma mRNA and protein in ischemic cortical astrocytes. Despite being brain-specific, the functional role of 14-3-3gamma in the brain still remains largely unknown. In this study, we show that among all the 14-3-3 isoforms, only the gamma isoform is inducible under ischemia in astrocytes. Furthermore, this upregulation of 14-3-3gamma may play a specific protective role in astrocytes under ischemia. Overexpression experiments and antisense treatment show that an elevation of 14-3-3gamma protein in astrocytes promotes survival, while a decrease in 14-3-3gamma enhances apoptosis in astrocytes under ischemia. Under ischemia, endogenous 14-3-3gamma binds p-Bad, thus preventing Bad from entering mitochondria to initiate apoptosis. Therefore, 14-3-3gamma is selectively induced during ischemia to protect astrocytes from apoptosis through p-Bad-related signaling.
Assuntos
Proteínas 14-3-3/metabolismo , Astrócitos/metabolismo , Isquemia Encefálica/metabolismo , Isquemia Encefálica/prevenção & controle , Proteínas de Transporte/metabolismo , Animais , Apoptose/genética , Apoptose/fisiologia , Astrócitos/patologia , Isquemia Encefálica/patologia , Camundongos , Camundongos Endogâmicos ICR , Fosforilação , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Proteína de Morte Celular Associada a bclAssuntos
Reação em Cadeia da Polimerase , Síndrome Respiratória Aguda Grave/diagnóstico , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/isolamento & purificação , Portador Sadio/diagnóstico , Humanos , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/genética , Sensibilidade e EspecificidadeAssuntos
Doenças das Aves/diagnóstico , Doenças das Aves/genética , Surtos de Doenças/prevenção & controle , Testes Genéticos/métodos , Orthomyxoviridae/genética , Reação em Cadeia da Polimerase/métodos , Síndrome Respiratória Aguda Grave/diagnóstico , Animais , Aves , Coronavirus/genética , Coronavirus/isolamento & purificação , Orthomyxoviridae/isolamento & purificação , Síndrome Respiratória Aguda Grave/genética , Síndrome Respiratória Aguda Grave/prevenção & controle , Síndrome Respiratória Aguda Grave/veterináriaRESUMO
Four-and-a-half LIM domain protein 1B (FHL1B) is an alternatively-spliced isoform of FHL1. In this study, FHL1B was demonstrated to interact with the ß catalytic subunit (Cß) of a type 2A protein phosphatase (PP2A) by yeast two-hybrid screening. Domain studies using a small-scale yeast two-hybrid interaction assay revealed the mediation of protein-protein interaction by FHL1B's C-terminus. Interaction between FHL1B and PP2A was further verified by co-immunoprecipitation. FHL1B was also shown to shuttle between nucleus and cytoplasm at different phases of the cell cycle. These data suggest that the FHL1B/PP2A(Cß) interaction may illustrate a novel cell-cycle regulatory pathway.
Assuntos
Domínio Catalítico , Ciclo Celular , Peptídeos e Proteínas de Sinalização Intracelular/metabolismo , Proteínas Musculares/metabolismo , Proteína Fosfatase 2/química , Proteína Fosfatase 2/metabolismo , Animais , Biocatálise , Linhagem Celular Tumoral , Humanos , Peptídeos e Proteínas de Sinalização Intracelular/genética , Espaço Intracelular/metabolismo , Proteínas com Domínio LIM , Camundongos , Proteínas Musculares/genética , Ligação Proteica , Transporte Proteico , Reprodutibilidade dos Testes , Deleção de Sequência , Especificidade por SubstratoAssuntos
Técnicas de Diagnóstico Molecular/métodos , Síndrome Respiratória Aguda Grave/diagnóstico , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/isolamento & purificação , Idoso , Idoso de 80 Anos ou mais , Sistemas Computacionais , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase/métodos , RNA Viral/genética , Coronavírus Relacionado à Síndrome Respiratória Aguda Grave/genética , Sensibilidade e EspecificidadeRESUMO
Newcastle disease (ND) is a contagious and widespread avian disease affecting most species of birds. ND virus (NDV) is the only member of the avian paramyxovirus serotype 1 (APMV1) causing ND outbreak in bird flocks. The technique of nucleic acid sequence-based amplification (NASBA) is a potential method to rapidly and reliably detect NDV isolates. Here, we describe an effective and unprecedented method for detecting NDV strains of all pathotypes. A conserved region of the fusion protein gene was used for designing oligonucleotides specific to all NDV pathotypes. The dynamic range of this NDV NASBA detection method is comparable to virus culture and therefore the NDV NASBA method is a potential alternative for NDV screening and surveillance.
Assuntos
DNA Viral/genética , Doença de Newcastle/diagnóstico , Vírus da Doença de Newcastle/genética , Vírus da Doença de Newcastle/isolamento & purificação , RNA Viral/genética , Animais , Aves , Galinhas , Primers do DNA , Amplificação de Genes , Vírus da Doença de Newcastle/classificação , Fenótipo , FilogeniaRESUMO
Bcl-2-associated death protein (Bad), a member of the Bcl family, directs astrocytes in primary cultures to enter or resist apoptosis during ischemia in vitro. Under ischemia, Bad was the only Bcl family member whose expression was upregulated significantly during the early stages of an ischemic insult. Increased endogenous Bad was translocated from the cytoplasm to mitochondria to induce apoptosis in astrocytes. Concurrently, ischemia also induced Bad phosphorylation specifically on Ser112 to promote survival. This site-specific phosphorylation of Bad was mediated by an early activation of the mitogen-activated protein kinase/extracellular signal-regulated protein kinase (MAPK/ERK) intracellular signaling pathway. This study demonstrates that ischemia-induced Bad plays a dual role in determining whether astrocytes enter or resist apoptosis after an ischemic insult.
Assuntos
Apoptose/fisiologia , Astrócitos/fisiologia , Proteínas de Transporte/metabolismo , Córtex Cerebral/citologia , Isquemia/metabolismo , Mutagênese Sítio-Dirigida/fisiologia , Animais , Animais Recém-Nascidos , Apoptose/efeitos dos fármacos , Western Blotting/métodos , Células Cultivadas , Citocromos c/metabolismo , Indução Enzimática/fisiologia , Corantes Fluorescentes/metabolismo , Regulação da Expressão Gênica/fisiologia , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Imuno-Histoquímica/métodos , Imunoprecipitação/métodos , Marcação In Situ das Extremidades Cortadas/métodos , Camundongos , Camundongos Endogâmicos ICR , Mitocôndrias/metabolismo , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Modelos Biológicos , Neurônios/efeitos dos fármacos , Fosfatidilinositol 3-Quinases/metabolismo , Fosforilação , Fatores de Tempo , Transfecção/métodos , Proteína de Morte Celular Associada a bclRESUMO
The 14-3-3 proteins exist predominantly in the brain and may play regulatory roles in cellular processes of growth, differentiation, survival, and apoptosis. The biological functions, however, of the various 14-3-3 isoforms (beta, epsilon, eta, gamma, and zeta) in the brain remain unclear. We have reported previously upregulation of 14-3-3gamma in ischemic astrocytes. In the present study, we report selective regulation of 14-3-3eta in cultured cerebral cortical neurons and astrocytes during in vitro development. In cultured neurons, gene expression levels of 14-3-3eta increase with culture age (0-10 days). Brain-derived neurotrophic factor and neurotrophin-3 upregulate 14-3-3eta gene expression. In cultured astrocytes, 14-3-3eta is downregulated with culture age (1-5 weeks). The gene expression level of 14-3-3eta is not affected by scratch injury in astrocytes or by ischemia in neurons. These data suggest a possible role of 14-3-3eta in growth and differentiation of neurons and astrocytes, indicating an intricate mechanism governing coordinated and well-controlled developmental events in the brain to ensure normal neural functions.
Assuntos
Proteínas 14-3-3/metabolismo , Astrócitos/metabolismo , Córtex Cerebral/citologia , Córtex Cerebral/embriologia , Regulação da Expressão Gênica no Desenvolvimento/fisiologia , Neurônios/metabolismo , Proteínas 14-3-3/classificação , Fatores Etários , Animais , Astrócitos/efeitos dos fármacos , Fator Neurotrófico Derivado do Encéfalo/farmacologia , Hipóxia Celular/fisiologia , Células Cultivadas , Embrião de Mamíferos , Regulação da Expressão Gênica no Desenvolvimento/efeitos dos fármacos , Camundongos , Fator de Crescimento Neural/farmacologia , Neurônios/efeitos dos fármacos , Neurotrofina 3/farmacologia , Isoformas de Proteínas/metabolismo , RNA Mensageiro/biossíntese , Reação em Cadeia da Polimerase Via Transcriptase Reversa/métodos , Fatores de Tempo , Ferimentos e Lesões/fisiopatologiaRESUMO
Neuroglobin (Ngb), a recently discovered intracellular respiratory globin in neurons, may play a crucial role in oxygen homeostasis in the brain. We report preliminary findings indicating the presence of functional neuroglobin in primary cultures of cerebral cortical astrocytes. Reverse transcription real-time polymerase chain reaction (RRT-PCR) and immunostaining confirmed such presence in cultured astrocytes isolated from newborn mouse brain. Ngb antisense treatment increased apoptosis in ischemic astrocytes. The discovery of Ngb in astrocytes may provide some insight into how oxygen homeostasis is regulated in the brain.
Assuntos
Astrócitos/metabolismo , Globinas/metabolismo , Proteínas do Tecido Nervoso/metabolismo , Animais , Células COS , Células Cultivadas , Proteína Glial Fibrilar Ácida/metabolismo , Globinas/genética , Homeostase/fisiologia , Camundongos , Camundongos Endogâmicos ICR , Proteínas do Tecido Nervoso/genética , Neuroglobina , Consumo de Oxigênio/fisiologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Regulação para CimaRESUMO
Neuronal differentiation and aging are known to involve many genes, which may also be differentially expressed during these developmental processes. From primary cultured cerebral cortical neurons, we have previously identified various differentially expressed gene transcripts from cultured cortical neurons using the technique of arbitrarily primed PCR (RAP-PCR). Among these transcripts, clone 0-2 was found to have high homology to rat and human synaptic glycoprotein. By in silico analysis using an EST database and the FACTURA software, the full-length sequence of 0-2 was assembled and the clone was named as mouse synaptic glycoprotein homolog 2 (mSC2). DNA sequencing revealed transcript size of mSC2 being smaller than the human and rat homologs. RT-PCR indicated that mSC2 was expressed differentially at various culture days. The mSC2 gene was located in various tissues with higher expression in brain, lung, and liver. Functions of mSC2 in neurons and other tissues remain elusive and will require more investigation.
Assuntos
Glicoproteínas/genética , Proteínas do Tecido Nervoso/genética , Neurônios/fisiologia , Sinapses/metabolismo , Sequência de Aminoácidos , Animais , Sequência de Bases , Células Cultivadas , Glicoproteínas/metabolismo , Humanos , Camundongos , Dados de Sequência Molecular , Proteínas do Tecido Nervoso/metabolismo , Neurônios/citologia , Ratos , Alinhamento de Sequência , Homologia de Sequência do Ácido Nucleico , Distribuição TecidualRESUMO
The genome of a novel foot-and-mouth disease virus, HKN/2002, was 8104 nucleotides (nt) in length (excluding the poly(C) tract and poly(A) tail) and was composed of a 1042-nt 5'-untranslated region (UTR), a 6966-nt open reading frame, and a 93-nt 3'-UTR. Genome sequences of HKN/2002 and other known FMDV strains were compared. The VP1, VP2, and VP3-based neighbor-joining (NJ) trees were divided into distinct clusters according to different serotypes, while other region-based NJ trees exhibited some degree of intercross among serotypes. Mutations in HKN/2002 were revealed, including frequent deletions and insertions in the G-H loop of VP1, and deletion involving 10 amino acid residues in the 3A protein. An evolutionary relationship of HKN/2002 with an Asian FMDV lineage isolated from a Hong Kong swine host in 1970 was postulated. A 43-nt deletion identified in the 5'-UTR of HKN/2002 possibly contributed to the loss of one pseudo-knot domain.
Assuntos
Vírus da Febre Aftosa/genética , Genoma Viral , Regiões 3' não Traduzidas , Regiões 5' não Traduzidas , Sequência de Aminoácidos , Sequência de Bases , Proteínas do Capsídeo , Clonagem Molecular , Deleção de Genes , Dados de Sequência Molecular , Mutação , Nucleotídeos/química , Oligopeptídeos/genética , Fases de Leitura Aberta , Filogenia , Estrutura Terciária de Proteína , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Especificidade da Espécie , Proteínas Virais/genéticaRESUMO
A foot-and-mouth disease virus (FMDV, HKN/2002) was isolated in Hong Kong in 2002. The nucleotide sequence of the 3D(pol) gene encoding the viral RNA-dependent RNA polymerase was determined and compared with that of the same gene from other FMDVs. The 3D(pol) gene was 1410 nucleotides in length encoding a protein of 470 amino acid residues. Sequence comparisons indicated that HKN/2002 belonged to serotype O. An evolutionary tree based on the 3D(pol) sequences of 20 FMDV isolates revealed that the nucleotide sequence of the HKN/2002 3D(pol) gene was most similar to those of isolates found in Taiwan in 1997, suggesting that they share a common ancestor. The amino acid sequence of the HKN/2002 3D(pol) gene was determined and aligned with those of representative isolates from seven other Picornaviridae genera. Eight highly conserved regions were detected, indicating a conserved functional relevance for these motifs. Alignment of 20 FMDV 3D(pol) amino acid sequences revealed a hypermutation region near the N-terminus that may help the virus evade host immune systems.
Assuntos
Vírus da Febre Aftosa/enzimologia , Vírus da Febre Aftosa/genética , RNA Viral , RNA Polimerase Dependente de RNA/genética , Motivos de Aminoácidos , Sequência de Aminoácidos , Sequência de Bases , Clonagem Molecular , Sequência Conservada , RNA Polimerases Dirigidas por DNA/química , Variação Genética , Hong Kong , Modelos Genéticos , Dados de Sequência Molecular , Mutação , Filogenia , Estrutura Terciária de Proteína , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Análise de Sequência de DNA , Homologia de Sequência de AminoácidosRESUMO
Infection of poultry with highly pathogenic avian influenza virus (AIV) can be devastating in terms of flock morbidity and mortality, economic loss, and social disruption. The causative agent is confined to certain isolates of influenza A virus subtypes H5 and H7. Due to the potential of direct transfer of avian influenza to humans, continued research into rapid diagnostic tests for influenza is therefore necessary. A nucleic acid sequence-based amplification (NASBA) method was developed to detect a portion of the haemagglutinin gene of avian influenza A virus subtypes H5 and H7 irrespective of lineage. A further NASBA assay, based on the matrix gene, was able to detect examples of all known subtypes (H1-H15) of avian influenza virus. The entire nucleic acid isolation, amplification, and detection procedure was completed within 6h. The dynamic range of the three AIV assays was five to seven orders of magnitude. The assays were sensitive and highly specific, with no cross-reactivity to phylogenetically or clinically relevant viruses. The results of the three AIV NASBA assays correlated with those obtained by viral culture in embryonated fowl's eggs.
Assuntos
Vírus da Influenza A/genética , Vírus da Influenza A/isolamento & purificação , Replicação de Sequência Autossustentável/métodos , Animais , Sequência de Bases , Aves , Embrião de Galinha , Primers do DNA/genética , Sondas de DNA/genética , Influenza Aviária/diagnóstico , Influenza Aviária/virologia , Sensibilidade e Especificidade , Especificidade da Espécie , SuínosRESUMO
Astrogliosis is an inevitable and rapid response of astrocytes to physical, chemical and pathological injuries. To study astrogliosis, we developed a reproducible in vitro model in which low temperature injury to cultured astrocytes could be induced by placing the culture dish onto a copper pipe pre-cooled by liquid nitrogen. Using this model, the relationship between the temperature decline and the severity of cellular damage was analyzed. An increase in the expression of some known injury-related proteins, such as glial fibrillary acidic protein (GFAP), immediate early response genes (IEGs), and heat shock proteins 70 (HSP70), was demonstrated in astrocytes after low temperature trauma. With the use of this low temperature trauma model, the flexibility in the temperature control and injury area may allow researchers to evaluate cryotherapy and cryosurgery, which could be applicable to future development of quality health care.
Assuntos
Astrócitos/patologia , Temperatura Baixa/efeitos adversos , Animais , Células Cultivadas , Genes Precoces/genética , Proteína Glial Fibrilar Ácida/biossíntese , Proteína Glial Fibrilar Ácida/genética , Proteínas de Choque Térmico HSP70/biossíntese , Imuno-Histoquímica , Camundongos , Proteínas Proto-Oncogênicas c-fos/biossíntese , Proteínas Proto-Oncogênicas c-fos/genética , Proteínas Proto-Oncogênicas c-jun/biossíntese , Proteínas Proto-Oncogênicas c-jun/genética , Proteínas Proto-Oncogênicas c-myc/biossíntese , Proteínas Proto-Oncogênicas c-myc/genéticaRESUMO
An enhanced polymerase chain reaction (PCR) assay to detect the coronavirus associated with severe acute respiratory syndrome (SARS-CoV) was developed in which a target gene pre-amplification step preceded TaqMan real-time fluorescent PCR. Clinical samples were collected from 120 patients diagnosed as suspected or probable SARS cases and analyzed by conventional PCR followed by agarose gel electrophoresis, conventional TaqMan real-time PCR, and our enhanced TaqMan real-time PCR assays. An amplicon of the size expected from SARS-CoV was obtained from 28/120 samples using the enhanced real-time PCR method. Conventional PCR and real-time PCR alone identified fewer SARS-CoV positive cases. Results were confirmed by viral culture in 3/28 cases. The limit of detection of the enhanced real-time PCR method was 10(2)-fold higher than the standard real-time PCR assay and 10(7)-fold higher than conventional PCR methods. The increased sensitivity of the assay may help control the spread of the disease during future SARS outbreaks.