Hey1 gene expression patterns during the development of branchial arches and facial prominences

espanolObjetivo. El presente estudio tuvo como objetivo describir detalladamente los patrones de expresion del gen Hey1, un efector de la via Notch durante el desarrollo de arcos branquiales y prominencias faciales. Materiales y metodos. Se incubaron huevos fertilizados de pollo (Gallus gallus) obtenidos de una granja local entre 37.5-38.5oC con humedad relativa del 70% hasta que los embriones alcanzaron los estadios HH14 hasta HH25 de Hamilton-Hamburger. Las sondas Hey1 marcadas con digoxigenina-UTP se generaron a partir de plasmidos linearizados con T3 polimerasa por transcripcion in vitro. Luego se realizo hibridacion in situ sobre embriones completos. Se obtuvieron al menos 3 repeticiones (n=3) para cada estadio. Para confirmar los resultados observados en embriones completos, se realizaron cortes sagitales y coronales de 10 µm. Resultados. Durante los estadios de desarrollo HH14 y HH18, la expresion del gen Hey1 se localizo en el endodermo de las bolsas branquiales. La expresion genica de Hey1 tambien se observo en el epitelio que cubre las prominencias maxilares y mandibulares durante las etapas de desarrollo HH19 y HH21, asi como en el epitelio nasal entre HH19 y HH25. Tambien se detectaron transcritos de Hey1 en el epitelio que cubre la prominencia frontonasal durante la etapa HH21. Conclusiones. Estos patrones de expresion sugieren la participacion de este componente de la via de senalizacion Notch en la morfogenesis craneofacial, posiblemente estableciendo patrones de segmentacion faringea durante las primeras etapas y / o regulando la proliferacion y diferenciacion celular durante las ultimas etapas del desarrollo facial. EnglishObjective. The present study aimed to describe in detail the expression patterns of the gene Hey1, an effector of the Notch pathway, during the development of branchial arches and facial prominences. Materials and methods. Fertilized chicken (Gallus gallus) eggs obtained from a local egg farm were incubated at 37.5 -38.5oC with 70% relative humidity until the embryos reached Hamilton-Hamburger stages HH14 through HH25. Digoxigenin-UTP labeled probes Hey1 were generated from linearized plasmids with either T3 polimerase for in vitro transcription. Whole-mount in situ hybridization was then performed. At least 3 replicates (n=3) were obtained for each stage. To confirm the results observed in whole embryos, sagittal and coronal cryosectioning was performed using a thickness of 10 µm. Results. During developmental stages HH14 and HH18, Hey1 gene expression was localized to the endoderm of branchial pouches. Hey1 gene expression was also observed in the epithelium that covers the maxillary and mandibular prominences during developmental stages HH19 and HH21, as well as in the nasal epithelium between HH19 and HH25. Transcripts were also detected in the epithelium that covers the frontonasal prominence during stage HH21. Conclusions. These expression patterns suggest the participation of this component of the Notch signaling pathway in craniofacial morphogenesis, possibly establishing pharyngeal segmentation patterns during early stages and/or regulating cell proliferation and differentiation during the late stages of facial development.