RESUMEN
In mice, homozygous Lgr4 inactivation results in hypoplastic kidneys. To understand better the role of LGR4 in kidney development, we performed an analysis of kidneys in Lgr4-/- embryos. We stained Lgr4-/- kidneys with anti-WT1 and anti-Cleaved Caspase3 antibodies at E16.5, and observed that the structures of the cap mesenchyme were disrupted and that apoptosis increased. In addition, the expression of PAX2, an anti-apoptotic factor in kidney development, was also significantly decreased at E16.5. We found that the LGR4 defect caused an increase in apoptosis in the peripheral mesenchyme during kidney development.
Asunto(s)
Regulación del Desarrollo de la Expresión Génica , Riñón/metabolismo , Organogénesis/genética , Receptores Acoplados a Proteínas G/genética , Animales , Apoptosis , Western Blotting , Caspasa 3/genética , Caspasa 3/metabolismo , Embrión de Mamíferos , Homocigoto , Riñón/embriología , Ratones , Ratones Noqueados , Factor de Transcripción PAX2/genética , Factor de Transcripción PAX2/metabolismo , Receptores Acoplados a Proteínas G/deficienciaRESUMEN
We previously reported that Lgr4 has a critical role in the morphogenesis of kidney, but the detailed functions of Lgr4 in kidney development have not been elucidated. In contrast to Lgr4 null mice with 129Ola × C57BL/6J mixed background, C57BL/6J-backcrossed Lgr4 null mice (Lgr4(-/-)) showed the severe phenotype of embryonic lethality and also had dilated tubules in kidneys at E16.5. Based on quantitative RT-PCR and in situ hybridization, branching morphogenesis at E15.5 in the Lgr4(-/-) was arrested earlier, and both DBA-lectin staining and immunohistochemical analysis using Aqp3 antibodies showed that the ureteric bud (UB) of Lgr4(-/-) kidneys underwent premature differentiation. Furthermore, quantitative RT-PCR and histological analysis suggested that the impaired UB differentiation was caused by down-regulation of the Wnt pathway and Gata3 in the Lgr4(-/-) kidneys. We demonstrate here that Lgr4 has a novel function for maintaining the UB in an undifferentiated state.
Asunto(s)
Diferenciación Celular/genética , Factor de Transcripción GATA3/genética , Factor de Unión 1 al Potenciador Linfoide/genética , Receptores Acoplados a Proteínas G/genética , Uréter/embriología , Proteínas Wnt/metabolismo , Animales , Regulación hacia Abajo/genética , Femenino , Factor de Transcripción GATA3/metabolismo , Regulación del Desarrollo de la Expresión Génica , Factor de Unión 1 al Potenciador Linfoide/metabolismo , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Morfogénesis/genética , Receptores Acoplados a Proteínas G/metabolismo , Receptores Acoplados a Proteínas G/fisiología , Transducción de Señal/genética , Factores de Tiempo , Uréter/metabolismoRESUMEN
Lgr4 is one of the genes identified as novel G protein-coupled receptor genes designated Lgr4-Lgr8, with high homology with FSH receptor, LH receptor, and TSH receptor genes, but studies of Lgr4-mutant mice have suggested that Lgr4 has essential functions in development. This is the first report describing the relationship between the functions of Lgr4 and female reproductive systems.