Phenotype Image Detail

Image

Caption

Fgf20 is necessary for formation of the lateral compartment of the organ of Corti. Phalloidin staining of P0 and P7 cochleae showing hair cells. In Fgf20^tm1.1Dor/Fgf20⁺ (Fgf20^betaGal/+) cochlea, (A) there is one row of inner hair cells (IHC) and three rows of outer hair cells (OHC) throughout the cochlea. At P0, apical hair cells are not fuly differentiated; by P7, apical differentiation is complete. In homozygous Fgf20^tm1.1Dor/Fgf20^tm1.1Dor (Fgf20^{betaGal/betaGal}) cochlea (B), the cochlear base (base) has one row of inner hair cells and two rows of outer hair cells. The mid-cochlea (middle) forms patches of hair cells with two rows of IHCs and three rows of OHCs separated by gaps that lack hair cells. The apex (apex) contains hair cells that are much less differentiated and the distal apex (end of apex) contains no identifiable hair cells. At P7, the hair cells in the distal apex of homozygous and heterozygous mutant cochlea are comparable. (C) Diagram showing the cochlear regions examined in (A, B); b, base; m, middle; a, apex, a', end of apex. (D) Quantification of hair cell numbers at P4. Total numbers of IHCs and OHCs were counted from heterozygous (n = 3) and homozygous (n = 3) cochlea. The numbers of IHCs were comparable, while the numbers of OHCs were decreased by 70% in homozygous compared to heterozygous cochlea. Total numbers of hair cells were decreased by 50% in homozygous cochlea. (E) Length of cochlea at P4. Homozygous cochlea length (n = 3) was decreased by 10% compared to heterozygotes (n = 3). (F, G) Quantification of supporting cell numbers at P0. (F) Number of supporting cells, identified by staining for Prox1 (Figure S3G, H), and hair cells, were counted from base, middle, and apex regions of the OC and normalized to 100 um from heterozygous (n = 6) and homozygous (n = 8) mice. IHC numbers were slightly increased while OHC numbers were decreased by 57% in homozygous compared to heterozygous cochlea. Numbers of Deiters' cells (DC) and outer pillar cells (OPC) were decreased by 52%, whereas numbers of inner pillar cels (IPC) were only slightly decreased in homozygous compared to heterozygous cochlea. (G) Ratio of hair cells and supporting cells in P0 cochlea. The ratio of outer comprtment cells (OHC, OPC, DC) to inner compartment cells (IHC, IPC) was decreased in homozygous compared to heterozygous cochlea. Small changes in the ratio of outer compartment supporting cells (DC+OPC) to OHCs and inner compartment supporting cells (IPC) to IHCs were observed. *p<0.01.

Copyright

This image is from Huh SH, PLoS Biol 2012 Jan;10(1):e1001231, and is displayed under the terms of the Creative Commons Attribution 4.0 International License. J:184501

Associated Alleles

Symbol	Name
Fgf20^tm1.1Dor	fibroblast growth factor 20; targeted mutation 1.1, David M Ornitz

Associated Genotypes

Allelic Composition	Genetic Background
Fgf20^tm1.1Dor/Fgf20^tm1.1Dor	involves: 129X1/SvJ * C57BL/6J