The zebrafish prospero homolog prox1 is required for mechanosensory hair cell differentiation and functionality in the lateral line

Background: The lateral line system in zebrafish is composed of a series of organs called neuromasts, which are distributed over the body surface. Neuromasts contain clusters of hair cells, surrounded by accessory cells. Results: In this report we describe zebrafish prox1 mRNA expression in the migrating primordium and in the neuromasts of the posterior lateral line. Furthermore, using an antibody against Prox1 we characterize expression of the protein in different cell types within neuromasts, and we show distribution among the supporting cells and hair cells. Conclusion: Functional analysis using antisense morpholinos indicates that prox1 activity is crucial for the hair cells to differentiate properly and acquire functionality, while having no role in development of other cell types in neuromasts.We thank Catalina Lafourcade and Florencio Espinoza for technical help; Herwig Baier and Hitoshi Okamoto for the pou4f3::GFP and pou4f1::mGFP transgenic fish, respectively; Kenna Shaw and Brant Weinstein for the SCM1 line; Vladimir Korzh for SqET20; Darren Gilmour for ClaudinB::GFP. MA and CGF were supported by grants from FONDECYT (1070867), ICM (P06- 039F) and UNAB (DI23-08/R). AP and FC were supported by grants from CARIPLO N.O.B.E.L. Molecular and cellular biology of tumor stem cell