The Molecular and Cellular Mechanisms of Zebrafish Lateral Line Development

Abstract

In aquatic vertebrates, the lateral line mechanosensory system allows for sensation of changes in water current and mediates such behaviors as schooling, predator avoidance, and mating. The lateral line forms from placodes that arise just rostral and caudal to the otic placode. Shortly after placode formation, groups of cells will delaminate from the placodes and begin migrating either throughout the head or down the trunk of the developing embryo. These migratory groups of cells are known as the sensory ridges (head) and posterior lateral line primordium (trunk). During migration, they deposit cell clusters containing hair cell precursors. Shortly after deposition, these clusters will differentiate into mechanosensory organs called neuromasts. In larvae and adults, the lateral line system continues to elaborate; this is accomplished through a differentiation of latent precursors (larvae) as well as a cellular budding process (larvae and adults), resulting in strings of neuromasts that populate the body of aquatic vertebrates. The zebrafish (Danio rerio) has emerged as an exquisite model to study the formation and function of the lateral line system. This chapter describes the development of the zebrafish lateral line and the associated axonal innervations that make up the mechanosensory system.