RESUMO
Producing polyclonal antibodies (IgY) in chickens has advantages over those obtained in other animal models, since they have been used as a tool for studying different proteins (NMDA glutamate receptor in our case, specifically the NR1 subunit). We produced specific antibodies against expression products by the alternative splicing of the gene encoding NMDA receptor NR1 subunit in adult rat brain. Three peptides corresponding to the splicing sites (N1, C1 and C2' cassettes) were designed, synthesised and used individually as antigens in hens. Specific immunoglobulins were purified from yolks. The antibodies were then used for purifying the NMDA receptor NR1 subunit using affinity chromatography coupling the three antibodies to the support.
La producción de anticuerpos policlonales en gallinas (IgY) tiene ventajas sobre anticuerpos obtenidos en otros modelos animales y se han empleado como una nueva herramienta para estudiar diferentes proteínas (el receptor de glutamate tipo NMDA en nuestro caso, específicamente la subunidad NR1). Produjimos anticuerpos específicos contra productos de expresión por splicing alternativo del gen que codifica la subunidad NR1 del receptor tipo NMDA en el cerebro de rata adulta. Se diseñaron 3 péptidos correspondientes a los sitios de splicing del gen (conocidos como casetes N1, C1 y C2'), se sintetizaron y se usaron individualmente como antígenos en gallinas. Inmunoglobulinas específicas se purificaron de las yemas. Los anticuerpos se usaron para purificar la subunidad NR1 del receptor tipo NMDA usando cromatografía de afinidad, a través del acople de los tres anticuerpos al soporte.
A produção de anticorpos policlonais (IgY) em galinhas tem vantagens sobre os obtidos em outros modelos animais e eles têm sido usados como uma ferramenta para o estudo de proteínas diferentes (NMDA receptor de glutamato no nosso caso, especificamente a subunidade NR1). Nós produzimos anticorpos específicos contra produtos de expressão pela splicing alternativo do gene que codifica receptor NMDA subunidade NR1 no cérebro de ratos adultos. Três peptídeos correspondentes aos locais de splicing (N1, C1 e C2' cassetes) foram concebidos, sintetizados e utilizados individualmente como antígenos em galinhas. Imunoglobulinas específicas foram purificadas a partir de gemas. Os anticorpos foram então usados para purificar o receptor NMDA subunidade NR1 utilizando cromatografia de afinidade, por meio da junção dos três anticorpos ao suporte.
RESUMO
El receptor ionotrópico de glutamato activado por N-metil-D-aspartato (iGluR-NMDA) es un complejo macromolecular heteromultimérico constituido por entre 3 y 5 subunidades de tres diferentes tipos, a saber: NR1, NR2A-D y NR3A y B. Se ha demostrado su participación activa en prácticamente todos los procesos fisiológicos, patológicos e intermediarios de efectos farmacológicos que ocurren en las células de tejidos excitables, inclusive se ha reportado su presencia en otros tejidos no excitables. En el sistema nervioso central (SNC) participa en los procesos de aprendizaje, memoria, plasticidad, diferenciación, migración de la célula neural y apoptosis. Además, en los eventos de índole farmacológica se ha demostrado su intervención en excitotoxicidad, drogadicción y alcoholismo. Surge entonces la pregunta de cómo un mismo complejo macromolecular puede participar en tantos y tan diversos procesos. La revisión de literatura en la que se demuestra la interacción del iGluR-NMDA con proteínas de señalización, soporte, adaptadoras, moduladoras, de adhesión celular, de citoesqueleto y enzimas reporta un conjunto de más de 160 moléculas que participan en las cascadas que generan las señales a diferentes niveles de interacción y con diferentes sustratos. En este artículo se presenta un modelo predictivo estructural y funcional que permite distinguir, por lo menos, tres rutas diferenciadas de señalización.
The ionotropic glutamate receptor activated by N-methyl-D-aspartate (iGluR-NMDA) is a multiheteromeric complex constituted from by three to five subunits belonging to by three different kinds of subunits known as NR1, NR2AD y NR3A y B. It is well established the participation of iGluR-NMDA complexes in a broad range of physiological, pathological, and as intermediary in pharmacological processes of neural systems. In the CNS, iGluR-NMDA participates in learning, memory, plasticity, neural differentiation, neural migration, and apoptosis, among others. In addition, from the pharmacological point of view the iGluR-NMDA is playing a role in excitotoxicity, drugs-addiction and other dependences. How the same complex can participate in a significant broad group of neural activities is a valid question after a literature review. A carefully analysis shows that iGluR-NMDA interacts, at some level, with a big number of intracellular proteins belonging to signaling proteins family, support proteins, modulator proteins, cytoskeleton, and enzymes, resulting in interactions with more than a 160 proteins, at different interaction levels and acting with intracellular proteins. In this work we report a proposal for a model of differential signaling cascade pathways generated by the iGluR-NMDA gating. The model shows at least the possibility of three different signaling pathways.
Assuntos
Humanos , Homeostase , N-Metilaspartato , Receptores Ionotrópicos de Glutamato , Previsões , Plasticidade NeuronalRESUMO
The ionotropic receptor of glutamate activated by N-methyl-D-aspartate (iGluR-NMDA) is a multiheteromeric complex constituted by at least three different types of subunits, encoded by seven different genes. The subunits of iGluR-NMDA have a complex system of regulation of their gene expression. Their expression is specific for each type of neural cell, as well as for the age of the organism. Moreover, there are reports that iGluR-NMDA expression is species-specific. Even though this macromolecular complex is very important in physiology and pathology of the central nervous system, knowledge to date about the regulatory elements controlling expression is scarce. We present the results of an in silico prediction of potential regulatory elements, some of which coincide with the few known experimentally. We also present the important differences regarding the presence and the localization of the regulatory elements among human, rat, and mouse species.
Assuntos
Proteínas de Transporte/genética , Regulação da Expressão Gênica , Genes Reguladores , Proteínas do Tecido Nervoso/genética , Receptores de N-Metil-D-Aspartato/genética , Algoritmos , Animais , Sistema Nervoso Central/fisiologia , Técnicas Genéticas , Genoma , Genoma Humano , Humanos , Camundongos , Modelos Biológicos , N-Metilaspartato/genética , RNA Mensageiro/metabolismo , Ratos , Software , Especificidade da EspécieRESUMO
Statistical analysis of amino acid patterns in approximately 160,000 alpha-helices in experimentally determined structures revealed di-, tri-, and tetrapeptides, whose frequencies deviate most from the statistical model. Importantly, some sequences were never found in alpha- helices. This fact was detected initially with tripeptides, where nearly 1% of the possible sequences were never seen in the helical segments. For tetrapeptides, this effect is very strong and significant; almost 43% of the possible sequences never appear in alpha-helices. It is possible that there are some steric and energetic restrictions that do not allow these tetrameric amino acid sequences to form alpha-helical structure.
