Specific expression of Kcna10, Pxn and Odf2 in the organ of Corti.
Bottom Line: The development of the organ of Corti and the highly specialized cells required for hearing involves a multitude of genes, many of which remain unknown.Kcna10, a tetrameric Shaker-like potassium channel, is expressed strongly in the hair cells themselves.The roles of these genes are yet to be elucidated, but their specific expression patterns imply potential functional significance in the inner ear.
Affiliation: Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK.Show MeSH
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Mentions: Pxn expression was cytoplasmic at all stages, and was never seen in the nuclei. Staining was visible in the organ of Corti from E14.5, in patches of tissue at the modiolar side of the cochlear duct (Fig. 1a). By E16.5, some expression of Pxn could be seen in most supporting tissues, particularly the Deiters’ cells and pillar cells, as well as below the basilar membrane where the scala tympani was opening up (Fig. 1b), but expression in the organ of Corti became much clearer at E18.5 when some expression also could be seen in all epithelial cells lining the cochlear duct (Fig. 1c). By far the strongest expression at E18.5 was, however, in the pillar cells (Fig. 1c). In all of these locations, a gradient of intensity was seen from the basal turn of the cochlea to the apex, with strongest expression at the base. This gradient remained in place through P0, although expression in all locations intensified (Fig. 1d). Expression was also noted in the inner layer of Reissner’s membrane, and to have intensified significantly in the marginal cells at P0. At P3, the general expression pattern was identical to that seen at P0, although expression in the pillar, Deiters’ and marginal cells had increased (Fig. 1e and f), and the root cell processes were showing moderate expression of Pxn (data not shown). However, at P5 expression levels in the marginal cells had decreased (Fig. 1h). All other expression levels and patterns remained the same as that seen at P3 (data not shown). In addition, at P3 and P5 discreet patches of Pxn expression could be seen in the otic capsule, perhaps marking developing osteocytes (Fig. 1j; Vatsa et al., 2008). In the vestibular system, Pxn expression was much simpler: heavy expression was seen in supporting cells, with expression also in the hair cells; expression levels generally increased from E16.5 through P5 (Fig. 1g and j). From E18.5 expression was also noted in cells lining the vestibular ducts, particularly the common crus (Fig. 1i and j). In adult mice, Pxn expression was strongest in the stria vascularis, root cell processes and the spiral ganglion. It was also present in the hair cells of the maculae and cristae, with marked expression in the dark cells adjacent to the crista (Fig. 1k–m).
Affiliation: Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, UK.