Fig. 8

Mice carrying the spdz allele (MHER colony) are profoundly deaf, with abnormal hair cell stereocilia at P5 and hair cell degeneration by P29. a Mean ABR thresholds of affected (orange triangles, n = 7) and unaffected (teal circles, n = 6) mice at P28-29. Error bars are standard deviations. b Expression of MYO7A (brown) in hair cells from the apical region of the organ of Corti (90–95% of the distance from base to apex) of mice at P28 (n = 3 affected, 3 unaffected), showing that hair cells are visible in affected mice (arrowheads, red for the inner hair cell and black for outer hair cells). Scale bar = 20 µm. c Scanning electron micrographs of the 12 kHz best-frequency region (65–70% of the distance from base to apex) of the organ of Corti in unaffected (n = 4) and affected (n = 3) mice at P29. Brackets indicate the inner hair cell row. Most hair bundles are missing. Scale bar = 10 µm. d Scanning electron micrographs of a homozygous mutant mouse at P4 (n = 3) and an age-matched wildtype, showing the 42 kHz best-frequency region (20% of the distance from base to apex). Brackets indicate the inner hair cell row; scale bar = 10 µm. Lower panels show a magnified view of inner hair cells in the same region (scale bar = 1 µm). e Schematic showing the known protein-coding isoforms of Espn and the location of the intronic disruption (red line). The splice junctions identified in brain cDNA are shown below; each line indicates a splice junction visible in at least one mouse. At the bottom is a schematic of the genomic DNA (gDNA) showing exons 14, 15 and the start of exon 16 in black, separated by introns in white (not to scale). The disruption in the mutant is shown by the addition of a red block in the intron. The “test” primer pair (red arrows) fails to amplify in mutant gDNA, and the “control” primer pair (black arrows) works for both wildtype and mutant. f Gel showing bands amplified using these primer pairs (Additional File 2: Table S3) on an affected mouse and an unaffected mouse. The size of ladder bands is shown at the side in bp. Data underlying plots in this figure are in Additional File 3