Mapa de destino y estudio de vías de señalización en el desarrollo del oído interno de pollo

Abstract

The vertebrate inner ear is a complex system responsible for balance and hearing. The otic anlage arises from a portion of the cephalic ectoderm, named the otic placode, which invaginates and then closes to form the otic vesicle. In the adult inner ear of mammals, the vestibular portion, involved in balance, is constituted by two maculae and three cristae. In birds, there are two additional maculae. The auditive portion, the basilar papilla in birds and organ of Corti in mammals, detects sound. The acquisition of all the competences of the otic primordium is probably the first step in the development of the inner ear. First of all, the preplacodal domain specifies and then determines its otic fate by inductive signals from the adjacent neuroectoderm and the underlying mesenchyme. As the development proceeds, the otic field acquires progressively its identity with an otic fate, finally acquiring an irreversible state of cell determination. Thus, the developing inner ear has at least three cell precursors: neuroblasts, sensory precursors and non-sensory precursors. The establishment of the compartments in the otic epithelium could be essential for regional identification and the specification of cell fate corresponding to domains of clonal restriction and defined by the border of the gene expression domains. The different molecular interactions which regulate the induction, specification, and determination of the otic anlage axes, especially the dorso-ventral and antero-posterior axes, have been a focus of research in developmental biology in the last decade.