Stage 16 otocysts cultured for 7 days develop hair cells and neurons, independent of the presence of mesenchymal tissue. (A) Incomplete removal of periotic mesenchyme is clearly visible in cryosections of otocysts cultured for seven days. The asterisk labels such an area of mesenchyme-derived cells with chondrocyte morphology that label poorly with phalloidin (shown in B), indicating lower levels of F-actin in mesenchymal derivatives. (B) Hair cells, visualized by green myosin VIIA immunofluorescence and neurons (red β-III tubulin immunofluorescence) develop in the presence of mesenchyme. Filamentous actin is visualized with phalloidin-labeling (blue fluorescence) (C) Mesenchyme-free otocysts do not display mesenchyme-derived cell morphologies. (D) Hair cells (green) and neurons (red) develop in mesenchyme-free otocysts. Filamentous actin is visualized with phalloidin-labeling (blue fluorescence). (E) β-III tubulin-positive neurites (red) appear to contact myosin VIIA-positive hair cells shown in green (arrows). (F) Hair cells develop hair bundles that can be visualized with antibody to espin (green fluorescence), hair cell antigen (red fluorescence), and filamentous actin (blue fluorescence).
Li et al. BMC Developmental Biology 2005 5:16 doi:10.1186/1471-213X-5-16