GATA3 is downregulated during hair cell differentiation in the mouse cochlea

GATA3 is a transcription factor expressed in the inner ear during the early stages of development. A monoclonal antibody revealed that it is expressed in spiral ganglion cells and in all cells of the developing auditory senso ry epithelium in the mouse before the hair cells differentiate at embryonic days 14-16. Expression decreases selectively in the hair cells as they dif ferentiate progressively from the base to the apex of the developing organ of Corti. GATA3 subsequently decreases in the supporting cells and cannot b e detected by immunofluorescence in any cell of the adult sensory epitheliu m. It is not expressed in the vestibular sensory epithelia or surrounding t issues from embryonic day 14. We suggest that GATA3 could act as a represso r of critical genes involved in cell differentiation in the organ of Corti, enabling a progressive formation of the adult cellular pattern.