Abstract
PURPOSE: The F-box protein S-phase kinase-associated protein 2 (Skp2) positively regulates the G1-S transition by controlling the stability of several G1 regulators, such as the cell cycle inhibitor p27. The mechanisms that regulate the expression of p27 in the inner ear have not been elucidated. The purpose of this study is to evaluate the role of Skp2 by regulating p27 during development of mammalian auditory system. MATERIALS AND METHODS: We examined the expression of Skp2, in combination with the expression of p27, a proliferating cell marker Ki67, and a differentiated hair cell marker myosin VIIa, in the developing inner ear of mice by immunofluorescence histochemistry. RESULTS: Our data showed that the expression of Skp2 in the auditory epithelia and neurons at an early stage of cell proliferation in the inner ear development. During the differentiation processes of inner ear development, the onset of p27 expression was observed and was accompanied with the down-regulation of Skp2 expression in the auditory epithelia. In addition, an alteration of the expression of Skp2 and p27 in the greater epithelial ridge and spiral ganglion neurons appeared after the differentiation of hair cells. CONCLUSIONS: These findings suggest that Skp2 is inversely expressed with p27, and plays a crucial role in the development of mammalian auditory system. [Jpn J Physiol 54 Suppl:S167 (2004)]
