RESUMEN
Similar amounts of N-cadherin and cadherin-7, the prototypes of type I and type II cadherin, induced cell-cell adhesion in murine sarcoma 180 transfectants, Ncad-1 and cad7-29, respectively. However, in the initial phase of aggregation, Ncad-1 cells aggregated more rapidly than cad7-29 cells. Isolated Ncad-1 and cad7-29 cells adhered and spread in a similar manner on fibronectin (FN), whereas aggregated cad7-29 cells were more motile and dispersed than aggregated Ncad-1 cells. cad7-29 cells established transient contacts with their neighbors which were stabilized if FN-cell interactions were perturbed. In contrast, Ncad-1 cells remained in close contact when they migrated on FN. Both beta-catenin and cadherin were more rapidly downregulated in cad7-29 than in Ncad-1 cells treated with cycloheximide, suggesting a higher turnover rate for cadherin-7-mediated cell-cell contacts than for those mediated by N-cadherin. The extent of FN-dependent focal adhesion kinase phosphorylation was much lower if the cells had initiated N-cadherin-mediated rather than cadherin-7-mediated cell adhesion before plating. On grafting into the embryo, Ncad-1 cells did not migrate and remained at or close to the graft site, even after 48 h, whereas grafted cad7-29 cells dispersed efficiently into embryonic structures. Thus, the adhesive phenotype of cadherin-7-expressing cells is regulated by the nature of the extracellular matrix environment which also controls the migratory behavior of the cells. In addition, adhesions mediated by different cadherins differentially regulate FN-dependent signaling. The transient contacts specifically observed in cadherin- 7-expressing cells may also be important in the control of cell motility.
Asunto(s)
Cadherinas/metabolismo , Movimiento Celular , Proteínas de la Matriz Extracelular/metabolismo , Transactivadores , Animales , Cadherinas/genética , Adhesión Celular , Moléculas de Adhesión Celular/metabolismo , Agregación Celular , Tamaño de la Célula , Trasplante de Células , Embrión de Pollo , Cicloheximida/farmacología , Proteínas del Citoesqueleto/metabolismo , Regulación hacia Abajo/efectos de los fármacos , Fibronectinas/metabolismo , Quinasa 1 de Adhesión Focal , Proteína-Tirosina Quinasas de Adhesión Focal , Integrinas/metabolismo , Ratones , Microscopía por Video , Fosforilación , Proteínas Tirosina Quinasas/metabolismo , Transducción de Señal , Transfección , Células Tumorales Cultivadas , beta CateninaRESUMEN
Melanocytes derived from pluripotent neural crest cells migrate initially in the dorsolateral pathway between the ectoderm and dermomyotome. To understand the role of specific proteins involved in this cell migration, we looked for a cellular model that mimics the in vivo behavior of melanoblasts, and that allows functional studies of their migration. We report here that wild-type embryonic stem (ES) cells are able to follow the ventral and dorsolateral neural crest pathways after being grafted into chicken embryos. By contrast, a mutant ES cell line deficient for beta1 integrin subunits, proteins involved in cell-extracellular interactions, had a severely impaired migratory behavior. Interestingly, ES cells deficient for Kit, the tyrosine kinase receptor for the stem cell factor (SCF), behaved similarly to wild-type ES cells. Thus, grafting mouse ES cells into chicken embryos provides a new cellular system that allows both in vitro and in vivo studies of the molecular mechanisms controlling dorsolateral migration.
Asunto(s)
Movimiento Celular/fisiología , Melanocitos/fisiología , Glicoproteínas de Membrana , Oxidorreductasas , Proteínas Proto-Oncogénicas c-kit/genética , Animales , Sitios de Unión , Biomarcadores , Línea Celular , Embrión de Pollo , Proteínas de Unión al ADN/genética , Inducción Embrionaria , Endotelina-3/genética , Fibronectinas/metabolismo , Colorantes Fluorescentes/metabolismo , Regulación del Desarrollo de la Expresión Génica , Integrina beta1/genética , Integrina beta1/metabolismo , Oxidorreductasas Intramoleculares/genética , Ratones , Ratones Mutantes , Factor de Transcripción Asociado a Microftalmía , Monofenol Monooxigenasa/genética , Mutación , Sistema Nervioso/citología , Sistema Nervioso/embriología , Proteínas/genética , Receptor de Endotelina B , Receptores de Endotelina/genética , Factores de Transcripción de la Familia Snail , Trasplante de Células Madre , Factores de Transcripción/genética , beta-Galactosidasa/genética , beta-Galactosidasa/metabolismoRESUMEN
Interactions between cells and extracellular matrix play a crucial role during development by controlling tissue remodelling and cell migration. Integrins are the main family of cell surface receptors for extracellular matrix. The knockout of integrin genes in mouse embryos has provided new insights into the function of these receptors during embryonic development and morphogenesis. The lethality observed either during embryonic life or after birth suggests that many integrins are essential.
Asunto(s)
Desarrollo Embrionario y Fetal/fisiología , Integrinas/genética , Animales , Regulación del Desarrollo de la Expresión Génica , Ratones , Ratones NoqueadosRESUMEN
We have analyzed the interaction of neural crest cells with fragments of fibronectin corresponding to the different spliced variants of the COOH-terminal cell-binding domain (COOH-ter CBD). We have shown that this domain can support cell adhesion and migration and that both the IIICS and HepII regions are involved in these events. The rate of locomotion is high, although undirectional, compared to that of whole fibronectin. Interactions with the COOH-ter CBD are controlled by alpha4beta1 and maybe other beta1 integrins and cell-surface proteoglycans. These receptors act cooperatively to mediate attachment, spreading, and migration on fibronectin.