RESUMO
Bone Morphogenetic Proteins (BMPs) have multiple activities in the developing spinal cord: they specify the identity of the dorsal-most neuronal populations and then direct the trajectories of dorsal interneuron (dI) 1 commissural axons. How are these activities decoded by dorsal neurons to result in different cellular outcomes? Our previous studies have shown that the diverse functions of the BMPs are mediated by the canonical family of BMP receptors and then regulated by specific inhibitory (I) Smads, which block the activity of a complex of Smad second messengers. However, the extent to which this complex translates the different activities of the BMPs in the spinal cord has remained unresolved. Here, we demonstrate that the receptor-activated (R) Smads, Smad1 and Smad5 play distinct roles mediating the abilities of the BMPs to direct cell fate specification and axon outgrowth. Smad1 and Smad5 occupy spatially distinct compartments within the spinal cord, with Smad5 primarily associated with neural progenitors and Smad1 with differentiated neurons. Consistent with this expression profile, loss of function experiments in mouse embryos reveal that Smad5 is required for the acquisition of dorsal spinal neuron identities whereas Smad1 is critical for the regulation of dI1 axon outgrowth. Thus the R-Smads, like the I-Smads, have discrete roles mediating BMP-dependent cellular processes during spinal interneuron development.
Assuntos
Receptores de Proteínas Morfogenéticas Ósseas/metabolismo , Proteínas Smad Reguladas por Receptor/metabolismo , Medula Espinal/embriologia , Medula Espinal/metabolismo , Animais , Proteínas Aviárias/antagonistas & inibidores , Proteínas Aviárias/genética , Proteínas Aviárias/metabolismo , Axônios/metabolismo , Sequência de Bases , Embrião de Galinha , Regulação da Expressão Gênica no Desenvolvimento , Imuno-Histoquímica , Hibridização In Situ , Interneurônios/citologia , Interneurônios/metabolismo , Camundongos , Camundongos Mutantes , Camundongos Transgênicos , Modelos Neurológicos , Neurogênese , RNA Interferente Pequeno/genética , Ratos , Proteínas Smad Reguladas por Receptor/antagonistas & inibidores , Proteínas Smad Reguladas por Receptor/genética , Proteína Smad1/antagonistas & inibidores , Proteína Smad1/genética , Proteína Smad1/metabolismo , Proteína Smad5/antagonistas & inibidores , Proteína Smad5/genética , Proteína Smad5/metabolismo , Medula Espinal/citologiaRESUMO
Several substances in urine were found to inhibit the radioimmunoassay of added gonococcal antigens. The supernatants of two-thirds of urine samples from male patients with either gonorrhoea or non-specific urethritis (NSU) were inhibitory. The inhibition caused by many, but not all, samples was reduced or completely abolished by the addition of soybean trypsin inhibitor (STI); STI-sensitive inhibition is thought to be due to proteolytic enzymes, probably from pus cells. Their inhibitory effect was shown to be due to their action on gonoccocal antigens and not on antibodies in the assay system. Some supernatants contained other inhibitors unaffected by STI; some of these were dialysable and others were not. Sediments from the urine of patients with NSU or gonorrhoea were often strongly inhibitory, but treatment with STI annulled all but very slight inhibition. STI-treated sediments could, therefore, be used in an assay designed to detect gonococcal antigens.
Assuntos
Antígenos de Bactérias/análise , Gonorreia/diagnóstico , Neisseria gonorrhoeae/imunologia , Radioimunoensaio/métodos , Urina/imunologia , Cistite/imunologia , Diagnóstico Diferencial , Feminino , Humanos , Imunoglobulinas/imunologia , Masculino , Peptídeo Hidrolases/imunologia , Uretrite/imunologiaRESUMO
About 30% of boar seminal plasma nitrogen is maximally precipitated at room temperature by 6 to 10 mM zinc in citrate solution at pH 8. A rise in the total nitrogen precipitated by 1 to 6 mM zinc is accompanied by a fall in the haemagglutinin titre of the supernatant fluid. At 6 mM zinc addition, 95% of the haemagglutinin is precipitated, but much of this is recoverable by re-solution of the zinc precipitate. Protein profile studies by gel-filtration chromatography of the zinc precipitate solution reveals a mixture of proteins, some of which are not by themselves zinc-precipitable.
