RESUMO
Fragile X syndrome, a common form of inherited mental retardation, is caused by the loss of fragile X mental retardation protein (FMRP). We have previously demonstrated that dFmr1, the Drosophila ortholog of the fragile X mental retardation 1 gene, plays a role in the proper maintenance of germline stem cells in Drosophila ovary; however, the molecular mechanism behind this remains elusive. In this study, we used an immunoprecipitation assay to reveal that specific microRNAs (miRNAs), particularly the bantam miRNA (bantam), are physically associated with dFmrp in ovary. We show that, like dFmr1, bantam is not only required for repressing primordial germ cell differentiation, it also functions as an extrinsic factor for germline stem cell maintenance. Furthermore, we find that bantam genetically interacts with dFmr1 to regulate the fate of germline stem cells. Collectively, our results support the notion that the FMRP-mediated translation pathway functions through specific miRNAs to control stem cell regulation.
Assuntos
Diferenciação Celular , Proteínas de Drosophila/metabolismo , Drosophila/metabolismo , Proteína do X Frágil da Deficiência Intelectual/metabolismo , Síndrome do Cromossomo X Frágil/metabolismo , Células Germinativas/citologia , MicroRNAs/metabolismo , Células-Tronco/citologia , Animais , Drosophila/citologia , Drosophila/genética , Proteínas de Drosophila/genética , Feminino , Proteína do X Frágil da Deficiência Intelectual/genética , Síndrome do Cromossomo X Frágil/genética , Células Germinativas/metabolismo , Humanos , MicroRNAs/genética , Ovário/citologia , Ovário/metabolismo , Ligação Proteica , Células-Tronco/metabolismoRESUMO
Increasingly complex networks of small RNAs act through RNA interference pathway to regulate gene expression. Recent evidence suggests that both development and proper function of central nervous system require intricate spatiotemporal expression of a wide repertoire of small regulatory RNAs. Misregulation of these small regulatory RNAs could contribute to the abnormalities in brain development that are associated with neurodevelopmental disorders. Here, we will review recent progress made toward understanding roles of small regulatory RNAs in neurodevelopmental disorders and discuss the potential involvement of newly discovered classes of small RNAs in these disorders.
Assuntos
Doenças do Sistema Nervoso/genética , RNA não Traduzido/metabolismo , Animais , Sistema Nervoso Central/metabolismo , Regulação Bacteriana da Expressão Gênica , Humanos , MicroRNAs/genética , MicroRNAs/metabolismo , Neurogênese , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , RNA não Traduzido/genéticaRESUMO
Sterigmatocystin, ST, is carcinogenic mycotoxin with toxicity second to aflatoxins, contaminated in foods- and feeds-stuff widely. A three-electrode system was employed to examine the response character of the covalently united ADTZ-MWNTs electrode to ST, and the results indicated that an oxidation peak of ST was observed at about +400 mv, the linear detection range of ST was from 4.16 x 10(-5) mg/ml (0.13 microM) to 1.33 x 10(-3) mg/ml (4.29 microM) with the detection limit at 0.13 microM. Compared to the corresponding results obtained from the MWNTs modified electrode that ADTZ was directly sediment (adsorbed) on it, the sensitivity of ours had been improved by two orders of magnitude, which could provide some important data to further research.
Assuntos
Técnicas Biossensoriais/instrumentação , Eletroquímica/instrumentação , Complexos Multienzimáticos/química , Nanotubos de Carbono/química , Esterigmatocistina/análise , Adsorção , Técnicas Biossensoriais/métodos , Eletroquímica/métodos , Enzimas Imobilizadas/química , Desenho de Equipamento , Análise de Falha de Equipamento , Análise de Alimentos/instrumentação , Contaminação de Alimentos/análise , Nanotubos de Carbono/ultraestrutura , Ligação Proteica , Esterigmatocistina/químicaRESUMO
Sterigmatocystin (ST), the secondary metabolite of many kinds of filamentous fungi, is a potent carcinogen structurally related to the aflatoxins (AFT). With similar chemical structure, sterigmatocystion behaves much the homogeneous properties to aflatoxins, both of these mycotoxins exhibit similar biological properties due to their bisfuranoid structure. Since the common, and even heavier pollution, found in foods and feeds-stuff, sterigmatocystion is more harmful than aflatoxins. The reported detection methods of sterigmatocystion included the Thin-layer Chromatography, the High-Performance-Liquid Chromatography, the Enzyme-Linked Immunosorbant Assay and the PCR detection to the toxic gene, however studies about both easy and inexpensive electro-chemical methods have not been found. Our previous studies had discovered that Sterigmatocystin (ST) exist similar sensitivity towards aflatoxin-detoxifizyme (ADTZ), which we had isolated from a fungus, as aflatoxin does. In this work, the preliminary study on electrochemical analysis and determination of ST with triplet electrode enzyme-biosensor system (Ag/AgCl as the reference electrode, Pt and Au as the pair and work electrode, respectively) was carried out. Multiwall-carbon-nanotube (MWNT) had been used to increase the electron transportation on electrode. In the research, the Au electrode was modified by MWNT-immobilized ADTZ, and then the voltammertric behavior of ST was studied by means of cyclic voltammogram analysis and different pulse analysis. Autoprobe CP Research Atomic Force Microscope and TECNAI 10 Transmission Electron Microscope, had been used to detect the MWNT as well as the surface of MWNT-modified ADTZ. The voltammertric behavior of ST was studied by means of cyclic voltammogram analysis and different pulse analysis. The results show that the red-ox peak potential of ST is at the point of -600 mV, the linear detection range is from 8.32 x 10(-5) to 66.56 x 10(-5) mg/mL, the detection limit is at 8.32 x 10(-5) mg/mL, and the response time is 10 seconds. This study provided a good basic work for further research.
