Molecular dissection of the migrating posterior lateral line primordium during early development in zebrafish. Danio rerio

The posterior lateral line system in zebrafish involves cell migration, proliferation and differentiation into mechanosensory cells. During development, a group of cranial placodal cells delaminate and become a coherent, migratory primordium that traverses the length of the fish to form this sensory system. As they migrate, the primordium deposits groups of cells called neuromasts, the specialized organs that contain the mechanosensory hair cells. The lateral line hair cells of fish are related to inner ear hair cells; therefore the primordium provides both a model for studying collective directional cell migration and the differentiation of sensory cells from multipotent progenitor cells. Through the combination of transgenic fish, Fluorescence Activated Cell Sorting and microarray analysis we identified a repertoire of key genes expressed in the migrating primordium and in differentiated neuromasts. We validated the specific expression in the primordium of a subset of the identified sequences by quantitative RT-PCR, and by in situ hybridization. We also show that interfering with the function of f11r and cd9b induces defects in its migratory behavior. Finally, pathway construction revealed functional relationships among the genes enriched in the migrating cell population. Our results demonstrate that this is a robust approach to globally analyze specific expression and we predict that many of the genes identified in this study will show critical functions in developmental and tumor progression process relating to posterior lateral line development. Overall design: The experiment was performed in two developmental stages, 36 and 48 hours post-fertilization. Two-condition experiment, GFP- (negative control) and GFP+ cells. Two biological repeats by stage, each by quadruplicate including a dye swap.