Int. J. Dev. Biol. 51: 409 - 414 (2007)
doi: 10.1387/ijdb.072273tm
© UPV/EHU Press

Analysis of Netrin 1 receptors during inner ear development

Tanja Matilainen, Maarja Haugas, Jordan A. Kreidberg1,2 and Marjo Salminen*

Developmental Biology Program, Institute of Biotechnology, University of Helsinki, Finland, 1Department of Medicine, The Children’s Hospital and 2Department of Pediatrics, Harvard Medical School, Boston, MA, USA

ABSTRACT Netrin 1 plays key roles in axon guidance and neuronal migration during central nervous system (CNS) development. Outside the CNS, Netrin 1 has been shown to be involved in epithelial morphogenesis of various organs. We have shown that Netrin 1 is essential for inner ear semicircular duct formation, but the involvement of Netrin 1 receptors in this process has remained unknown. Netrin 1 receptors include members of the Deleted in colorectal cancer (Dcc), Unc5-homologue and integrin families. Here we have analysed the expression of these receptor genes during inner ear development and verified the inner ear phenotypes of several receptor mutant mice. Special interest was directed to receptors that could cooperate with Netrin 1 during semicircular duct formation. We show that Neogenin (Neo1), Unc5c as well as integrin b1 (Itgb1) are expressed in periotic mesenchyme, while Dcc, Unc5b, Unc5c, Itga3, Itga6 and Itgb1 are expressed in different parts of the otic epithelium. In spite of the broad and strong expression of several receptors in ear region, none of the analysed receptor mutant embryos showed any defects in inner ear development.

Keywords:

epithelial morphogenesis, semicircular duct, Dcc, Unc5, integrin

*Corresponding author e-mail: marjo.salminen@helsinki.fi