○Hironori Wada1,2,Koichi Kawakami2,3
Postembryonic development of the lateral line neuromasts in zebrafish
1)PRESTO, JST, 2)NIG, 3)SOKENDAI
The lateral line system comprises a large number of mechanosensory receptors, the neuromasts, distributed over the body surface of fish.
The embryonic neuromasts are established by a primordium originates from the lateral line placodes, but these account for only a small proportion of adult neuromasts.
In the previous study, we demonstrated that the embryonic neuromast gives rise to a series of accessory neuromasts by a serial budding process, which accounts for the increasing
number of neuromasts in region-specific manners. Thus, the lateral line system is an excellent model to understand the mechanisms of organ remodeling during postembryonic development.
In this study, to understand the molecular basis for the budding process, we searched for genes which express in the forming neuromasts of zebrafish. We showed that Fgf pathway genes and
Wnt inhibitory factors, Dkks, were strongly expressed in the differentiating neuromasts. We also showed that the Wnt-signaling downstream activities were detectable only in the budding cells.
To reveal roles of the Wnt signaling during the budding process, we knocked-down Dkk functions by antisense morpholino oligonucleotides,
and overexpressed Dkks in specific cells using the Gal4-UAS system. Here, we report preliminary results on roles of the Wnt signaling during postembryonic remodeling of the lateral line system.