RESUMEN
The glial cell line-derived neurotrophic factor (GDNF)/RET tyrosine kinase signaling pathway plays crucial roles in the development of the enteric nervous system (ENS) and the kidney. Tyrosine 1062 (Y1062) in RET is an autophosphorylation residue that is responsible for the activation of the PI3K/AKT and RAS/MAPK signaling pathways. Mice lacking signaling via Ret Y1062 show renal hypoplasia and hypoganglionosis of the ENS although the phenotype is milder than the Gdnf- or Ret-deficient mice. Sprouty2 (Spry2) was found to be an antagonist for fibroblast growth factor receptor (FGFR) and acts as an inhibitory regulator of ERK activation. Spry2-deficient mice exhibit hearing loss and enteric nerve hyperplasia. In the present study, we generated Spry2-deficient and Ret Y1062F knock-in (tyrosine 1062 is replaced with phenylalanine) double mutant mice to see if abnormalities of the ENS and kidney, caused by loss of signaling via Ret Y1062, are rescued by a deficiency of Spry2. Double mutant mice showed significant recovery of ureteric bud branching and ENS development in the stomach. These results indicate that Spry2 regulates downstream signaling mediated by GDNF/RET signaling complex in vivo.
Asunto(s)
Anomalías del Sistema Digestivo/genética , Factor Neurotrófico Derivado de la Línea Celular Glial/metabolismo , Riñón/anomalías , Proteínas de la Membrana/deficiencia , Proteínas Proto-Oncogénicas c-ret/metabolismo , Transducción de Señal/fisiología , Proteínas Adaptadoras Transductoras de Señales , Análisis de Varianza , Animales , Western Blotting , Cartilla de ADN/genética , Anomalías del Sistema Digestivo/metabolismo , Sistema Nervioso Entérico/patología , Técnicas de Sustitución del Gen , Genotipo , Técnicas Histológicas , Hiperplasia/etiología , Hiperplasia/patología , Inmunohistoquímica , Péptidos y Proteínas de Señalización Intracelular , Riñón/metabolismo , Riñón/patología , Ratones , Ratones Mutantes , Reacción en Cadena de la Polimerasa , Proteínas Serina-Treonina Quinasas , Proteínas Proto-Oncogénicas c-ret/genética , Receptores de Factores de Crecimiento de Fibroblastos/antagonistas & inhibidores , Transducción de Señal/genéticaRESUMEN
Disrupted-In-Schizophrenia 1 (DISC1), a susceptibility gene for major psychiatric disorders, regulates neuronal migration and differentiation during mammalian brain development. Although roles for DISC1 in postnatal neurogenesis in the dentate gyrus (DG) have recently emerged, it is not known how DISC1 and its interacting proteins govern the migration, positioning, and differentiation of dentate granule cells (DGCs). Here, we report that DISC1 interacts with the actin-binding protein girdin to regulate axonal development. DGCs in girdin-deficient neonatal mice exhibit deficits in axonal sprouting in the cornu ammonis 3 region of the hippocampus. Girdin deficiency, RNA interference-mediated knockdown, and inhibition of the DISC1/girdin interaction lead to overextended migration and mispositioning of the DGCs resulting in profound cytoarchitectural disorganization of the DG. These findings identify girdin as an intrinsic factor in postnatal development of the DG and provide insights into the critical role of the DISC1/girdin interaction in postnatal neurogenesis in the DG.
Asunto(s)
Giro Dentado/embriología , Giro Dentado/crecimiento & desarrollo , Proteínas de Microfilamentos/metabolismo , Neurogénesis/fisiología , Proteínas de Transporte Vesicular/metabolismo , Análisis de Varianza , Animales , Animales Recién Nacidos , Bromodesoxiuridina/metabolismo , Diferenciación Celular/genética , Movimiento Celular/genética , Células Cultivadas , Chlorocebus aethiops , Giro Dentado/citología , Estimulación Eléctrica/métodos , Embrión de Mamíferos , Regulación del Desarrollo de la Expresión Génica/genética , Conos de Crecimiento/fisiología , Humanos , Inmunoprecipitación/métodos , Potenciales de la Membrana/efectos de los fármacos , Potenciales de la Membrana/genética , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Proteínas de Microfilamentos/deficiencia , Proteínas de Microfilamentos/genética , Proteínas del Tejido Nervioso/genética , Proteínas del Tejido Nervioso/metabolismo , Neurogénesis/genética , Neuronas/citología , Neuronas/fisiología , Técnicas de Placa-Clamp , Unión Proteica , Estructura Terciaria de Proteína/fisiología , Interferencia de ARN/fisiología , Ratas , Transfección/métodos , Proteínas de Transporte Vesicular/deficiencia , Proteínas de Transporte Vesicular/genéticaRESUMEN
Polycystic kidney disease (PKD) is a common hereditary disease in humans. Recent studies have shown an increasing number of ciliary genes that are involved in the pathogenesis of PKD. In this study, the Gli-similar3 (glis3) gene was identified as the causal gene of the medaka pc mutant, a model of PKD. In the pc mutant, a transposon was found to be inserted into the fourth intron of the pc/glis3 gene, causing aberrant splicing of the pc/glis3 mRNA and thus a putatively truncated protein with a defective zinc finger domain. pc/glis3 mRNA is expressed in the epithelial cells of the renal tubules and ducts of the pronephros and mesonephros, and also in the pancreas. Antisense oligonucleotide-mediated knockdown of pc/glis3 resulted in cyst formation in the pronephric tubules of medaka fry. Although three other glis family members, glis1a, glis1b and glis2, were found in the medaka genome, none were expressed in the embryonic or larval kidney. In the pc mutant, the urine flow rate in the pronephros was significantly reduced, which was considered to be a direct cause of renal cyst formation. The cilia on the surface of the renal tubular epithelium were significantly shorter in the pc mutant than in wild-type, suggesting that shortened cilia resulted in a decrease in driving force and, in turn, a reduction in urine flow rate. Most importantly, EGFP-tagged pc/glis3 protein localized in primary cilia as well as in the nucleus when expressed in mouse renal epithelial cells, indicating a strong connection between pc/glis3 and ciliary function. Unlike human patients with GLIS3 mutations, the medaka pc mutant shows none of the symptoms of a pancreatic phenotype, such as impaired insulin expression and/or diabetes, suggesting that the pc mutant may be suitable for use as a kidney-specific model for human GLIS3 patients.
Asunto(s)
Mutación , Enfermedades Renales Poliquísticas/genética , Factores de Transcripción/genética , Dedos de Zinc , Animales , Secuencia de Bases , Proliferación Celular , Cartilla de ADN , Colorantes Fluorescentes , Técnicas de Silenciamiento del Gen , Hibridación in Situ , Oryzias , Páncreas/metabolismo , Enfermedades Renales Poliquísticas/patología , Fracciones Subcelulares/metabolismoRESUMEN
Glis3 is a member of the Gli-similar subfamily. GLIS3 mutations in humans lead to neonatal diabetes, hypothyroidism, and cystic kidney disease. We generated Glis3-deficient mice by gene-targeting. The Glis3(-/-) mice had significant increases in the basal blood sugar level during the first few days after birth. The high levels of blood sugar are attributed to a decrease in the Insulin mRNA level in the pancreas that is caused by impaired islet development and the subsequent impairment of Insulin-producing cell formation. The pancreatic phenotypes indicate that the Glis3-deficient mice are a model for GLIS3 mutation and diabetes mellitus in humans.
Asunto(s)
Diabetes Mellitus Tipo 1/genética , Diabetes Mellitus Tipo 1/metabolismo , Transactivadores/deficiencia , Animales , Animales Recién Nacidos , Secuencia de Bases , Glucemia/metabolismo , Carboxipeptidasas A/metabolismo , Cartilla de ADN/genética , Proteínas de Unión al ADN , Diabetes Mellitus Tipo 1/patología , Modelos Animales de Enfermedad , Humanos , Recién Nacido , Insulina/genética , Islotes Pancreáticos/metabolismo , Islotes Pancreáticos/patología , Ratones , Ratones Noqueados , Mutación , Páncreas/metabolismo , Páncreas/patología , ARN Mensajero/genética , ARN Mensajero/metabolismo , Proteínas Represoras/genética , Transactivadores/genética , Factores de Transcripción/deficiencia , Factores de Transcripción/genéticaRESUMEN
We provide an overview of glomerulogenesis in medaka from the embryo to the adult by means of in situ hybridization with the wt1 gene as a marker as well as histology and three-dimensional images. The pronephric glomus starts to develop in the intermediate mesoderm during early somitogenesis, is completed before hatching, and persists throughout the lifetime of the fish. Within 5 days after hatching, mesonephric glomerulus formation begins in the caudomedial end of the pronephric sinus and duct area. The number of glomeruli reaches approximately 200-300 in each kidney within 2 months after hatching. wt1 expression during nephron maturation served as a marker for the formation of the mesenchymal condensate and the nephrogenic body. Existence of mesenchymal condensates and persistence of wt1 expression in the adult kidney suggest that the mesonephros retains precursor cells that may be capable of contributing to neoglomerulogenesis during adulthood.
