The zebrafish (Danio rerio) lateral line system consists of mechanoreceptive organs called neuromasts (Figure), which is closely related to the auditory system of higher vertebrates. The lateral line is used to sense water motion, thereby enabling fish to detect prey, avoid predators and swim in the coordinated direction commonly observed in schooling fish. The posterior lateral line (pLL) is established when a cluster of cells, known as the primordium detaches from the lateral line placode located just behind the developing ear, and migrates to the tip of the tail by periodically depositing neuromasts. The lateral line is a relatively simple structure found in most aquatic vertebrates and can serve as an excellent in vivo model to study fundamental developmental mechanisms including cell migration, cell proliferation, cell fate determination and organogenesis. The mechanisms governing the primordium migration, segmentation and neuromast deposition are relatively well understood. Much less is known about how the polarized rosettes of cells are organized and develop into functional neuromasts of a particular shape and size. I plan to determine the mechanism of neuromast formation, specifically, to figure out if there is a cell or a group of cells in the middle of the neuromast, which organizes its construction, or whether the neuromast formation is regulated by the “rosette gene”, which is expressed in all cells of the future neuromast. Most importantly, results from my studies will help to better understand tissue polarization and organ size control mechanisms, crucial for the developmental biology and cancer fields.
Sensory cells known as “hair cells” (center) are integral to the zebrafish lateral line organ, the neuromast.