RESUMEN
Defects of motile cilia cause primary ciliary dyskinesia (PCD), characterized by recurrent respiratory infections and male infertility. Using whole-exome resequencing and high-throughput mutation analysis, we identified recessive biallelic mutations in ZMYND10 in 14 families and mutations in the recently identified LRRC6 in 13 families. We show that ZMYND10 and LRRC6 interact and that certain ZMYND10 and LRRC6 mutations abrogate the interaction between the LRRC6 CS domain and the ZMYND10 C-terminal domain. Additionally, ZMYND10 and LRRC6 colocalize with the centriole markers SAS6 and PCM1. Mutations in ZMYND10 result in the absence of the axonemal protein components DNAH5 and DNALI1 from respiratory cilia. Animal models support the association between ZMYND10 and human PCD, given that zmynd10 knockdown in zebrafish caused ciliary paralysis leading to cystic kidneys and otolith defects and that knockdown in Xenopus interfered with ciliogenesis. Our findings suggest that a cytoplasmic protein complex containing ZMYND10 and LRRC6 is necessary for motile ciliary function.
Asunto(s)
Cilios/genética , Síndrome de Kartagener/genética , Proteínas/genética , Sistema Respiratorio/metabolismo , Proteínas Supresoras de Tumor/genética , Animales , Autoantígenos/genética , Autoantígenos/metabolismo , Dineínas Axonemales/genética , Dineínas Axonemales/metabolismo , Biomarcadores/metabolismo , Proteínas de Ciclo Celular/genética , Proteínas de Ciclo Celular/metabolismo , Cilios/metabolismo , Cilios/patología , Proteínas del Citoesqueleto , Exoma , Regulación de la Expresión Génica , Secuenciación de Nucleótidos de Alto Rendimiento , Humanos , Síndrome de Kartagener/metabolismo , Síndrome de Kartagener/patología , Masculino , Proteínas Asociadas a Microtúbulos/genética , Proteínas Asociadas a Microtúbulos/metabolismo , Mutación , Linaje , Unión Proteica , Estructura Terciaria de Proteína , Proteínas/metabolismo , Ratas , Sistema Respiratorio/patología , Proteínas Supresoras de Tumor/metabolismo , Xenopus laevis/genética , Xenopus laevis/metabolismo , Pez Cebra/genética , Pez Cebra/metabolismoRESUMEN
Neural progenitor cells in the pseudostratified neuroepithelium in vertebrates undergo interkinetic nuclear migration, which results in mitotic cells localized to the apical surface. Interphase nuclei are distributed throughout the rest of the epithelium. How mitosis is coordinated with nuclear movement is unknown, and the mechanism by which the nucleus migrates apically is controversial. Using time-lapse confocal microscopy, we show that nuclei migrate apically in G2 phase via microtubules. However, late in G2, centrosomes leave the apical surface after cilia are disassembled, and mitosis initiates away from the apical surface. The mitotic cell then rounds up to the apical surface, which is an actin-dependent process. This behavior is observed in both chicken neural-tube-slice preparations and in mouse cortical slices, and therefore is likely to be a general feature of interkinetic nuclear migration. We propose a new model for interkinetic nuclear migration in which actin and microtubules are used to position the mitotic cell at the apical surface.
Asunto(s)
Núcleo Celular/fisiología , Mitosis/fisiología , Modelos Biológicos , Células-Madre Neurales/fisiología , Células Neuroepiteliales/citología , Animales , Centrosoma/fisiología , Embrión de Pollo , Electroporación , Fase G2/fisiología , Ratones , Microscopía Confocal , Microtúbulos/fisiología , Células Neuroepiteliales/fisiología , Imagen de Lapso de TiempoRESUMEN
During interkinetic nuclear migration (INM), the nuclei in many epithelial cells migrate between the apical and basal surfaces, coordinating with the cell cycle, and undergoing cytokinesis at the apical surface. INM is observed in a wide variety of tissues and species. Recent advances in time-lapse microscopy have provided clues about the mechanisms and functions of INM. Whether actin or microtubules are responsible for nuclear migration is controversial. How mitosis is initiated during INM is poorly understood, as is the relationship between the cell cycle and nuclear movement. It is possible that the disagreements stem from differences in the tissues being studied, since epithelia undergoing INM vary greatly in terms of cell height and cell fates. In this review we examine the reports addressing the mode and mechanisms that regulate INM and suggest possible functions for this dramatic event.