PAX6 protein in neuromasts of the lateral line system of salamanders (Eurycea)

Abstract

PAX6 is well known as a transcription factor that drives eye development in animals as widely divergent as flies and mammals. In addition to its localization in eyes, PAX6 expression has been reported in the central nervous system, the pancreas, testes, Merkel cells, nasal epithelium, and developing cells of the inner ear. Here we show that PAX6 is also found in the mechanosensory neuromasts of the lateral line system in paedomorphic salamanders of the genus Eurycea. Using immunohistochemistry and confocal microscopy, we found that PAX6 is extranuclear, and antibody labeling is most intense in the apical appendages of the hair cells of the neuromast. This extranuclear localization raises the possibility of an as yet undescribed function for PAX6 as a cytoskeleton-associated protein.