Role of diffusible and transcription factors in inner ear development: implications in regeneration

L.M. Frago1, G. Camarero1, S. Cañón1, C. Pañeda1, C. Sanz1, Y. Leon1, F. Giraldez2 and I. Varela-Nieto1

1Institute of Biomedical Research "Alberto Sols", CSIC-UAM, Madrid, Spain and 2Institute of Biology and Molecular Genetic (IBGM), University of Valladolid-CSIC, School of Medicine, Valladolid, Spain

Offprint requests to: Dr. Isabel Varela-Nieto, Instituto de Investigaciones Biomédicas "Alberto Sols", CSIC-UAM, Arturo Duperier 4, 28029 Madrid, Spain. Fax: 34-91-5854587. e-mail: ivarela@biomed.iib.uam.es

Summary. Organogenesis involves a dynamic balance of the mechanisms regulating cell division, differentiation and death. The development of the chicken embryo inner ear offers a well-characterised model at the morphological level to study which signals are implicated in the modulation of cellular activation and commitment. The early developmental decisions that control the origin of the inner ear elements are just beginning to be identified by complementary in vivo and in vitro studies. Insulin-like growth factor-I (IGF-I) and nerve growth factor (NGF) are among the best characterised diffusible factors acting during inner ear development. Although the cellular actions of these factors are beginning to be understood, the signalling pathways triggered by them still remain largely unknown. In this context, viral vehicles can be used to deliver genes and then analyse their functional roles during inner ear development. A model is proposed where the actions of IGF-I and NGF contribute to the combinatorial expression of Jun and Fos family members in particular domains of the otic vesicle. Some of these mechanisms may be also implicated in otic regeneration. Histol. Histopathol. 15, 657-666 (2000)

Key words: Apoptosis, Insulin-like growth factor-I, Nerve growth factor, RCAS retroviral vectors, Jun signalling pathways

DOI: 10.14670/HH-15.657