Phenotype Image Detail

Image

Caption

Stereocilia on wild type and Rdx^tm1Sts/Rdx^tm1Sts cochlear hair cells of adult and newborn mice. A: Scanning electron micrographs (A-F) and whole-mount immunofluorescence micrographs for radixin and ezrin (G-J) of the wild type (Rdx^+/+) and Rdx^tm1Sts/Rdx^tm1Sts (Rdx^-/-) organ of Corti at 40 days of age (P40). The levels of outer hair cells (blue arrow) and inner hair cells (black arrow) are shown. At low magnification in the scanning electron micrograph of the wild type organ of Corti (A), the luminal surface is characterized by three rows of outer hair cells (blue arrow) and one row of inner hair cells (black arrow). Outer hair cells bear stereocilia arranged regularly in the form of a letter W (C), and inner hair cells have more disorganized arrays of stereocilia (E). In the mutant organ of Corti (B), no significant abnormalities are detected in the cellular arrangements on the luminal sruface, but the morphology of the stereocilia on both the outer (blue arrow) and inner (black arrow) hair cells is severely affected. In mutant outer hair cells, instead of regularly arranged stereocilia, 1-3 residual knoblike protrusions are observed on their apical surface (D). Mutant inner hair cells bear several shorter fused irregularly shaped protrusions instead of long stereocilia (F). By immunostaining, in the mutant organ of Corti (H and J), no staining for radixin is detected without any increase in the staining intensities for ezrin. Bars: A and B, 10um; C and D, 2um; E-F, 1um; G-J, 20um. B: Scanning electron micrographs (A-F) and whole-mount immunofluorescence micrographs for radixin and ezrin (G-J) of the wild type and mutant organ of Corti at 1 day of age (P1). Scanning electron microscopic images of the cochlea of P1 mutant mice (B,D and F) are indistinguishable from those in the wild type mice (A,C and E). In addition to stereocilia arrays carrying central tubulin-based kinocilium (arrows in C and D), hair cells as well as supporting cells are covered with large numbers of short conventional microvilli that have mostly disappeared in adult mice. Whole-mount immunostaining reveals that in the P1 wild type organ of Corti, radixin is highly enriched in stereocilia of inner and outer hair cells as well as the apical surface of hair and supporting cells (I), but in contrast to adult mice ezrin is also detected in stereocilia, weakly but clearly (G, arrowheads). In the mutant organ of Corti, instead of radixin, ezrin is highly concentrated at stereocilia on both inner and outer hair cells, (H, arrowheads). Bars, A and B, 10um; C and D, 2um; E and F, 1um; G-J, 20um.

Copyright

This image is from Kitajiri S, J Cell Biol 2004 Aug 16;166(4):559-70, and is displayed under the terms of the Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License. J:124151

Associated Alleles

Symbol	Name
Rdx^tm1Sts	radixin; targeted mutation 1, Shoichiro Tsukita

Associated Genotypes

Allelic Composition	Genetic Background
Rdx^tm1Sts/Rdx^tm1Sts	involves: 129S4/SvJae * C57BL/6