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Fig. 1 | Molecular Brain

Fig. 1

From: Microtubule-associated protein 1 A and tubby act independently in regulating the localization of stereocilin to the tips of inner ear hair cell stereocilia

Fig. 1

Wild-type MAP1A can rescue hearing impairment and preserve the localization of stereocilin to the tips of stereocilia in the absence of tubby protein. A Tubflox/flox mice were crossed with E2a-Cre mice expressing Cre in germ cells to produce null mutant mice. B Absence of a tubby protein band at the expected molecular size of approximately 63 kDa in western blots of the brain lysates from tubby mice and Tub-null mice. C Immunostaining of stereocilin in the stereocilia of 5–7-week-old control B6J (wild-type or Tub±) and Tub-null mice. A representative image from one of three experiments is shown. Arrows indicate the localization of stereocilin in the stereocilia. Scale bars: low-magnification images, 5 mm; high-magnification images, 0.5 mm. D, E ABR (D) and DPOAE (E) were measured in 5–7-week-old control (wild-type or Tub±), Tub−/− (Tub−/−; Map1aB6) and Tub−/−; Map1aAKR mice. Tub-null mice were crossed with AKR/N mice which have a Map1aAKR allele. Tub±; Map1aAKR mice were crossed together to generate Tub−/−; Map1aAKR mice. *P < 0.05, **P < 0.01, ***P < 0.001 compared to Tub−/−; Map1aAKR mice. n = 4–6. F, G Tubflox/flox mice were crossed with Pax2-Cre mice. Tub+/flox; Pax2-Cre mice were crossed together to generate Tubflox/flox; Pax2-Cre mice. ABR (F) and DPOAE (G) were measured in 5–7-week-old Tubflox/flox and Tubflox/flox; Pax2-Cre mice. *P < 0.05, **P < 0.01, ***P < 0.001 compared to Tubflox/flox mice. n = 4. H Immunostaining of stereocilin was performed in control B6J (wild-type or Tub±), Tub−/− (Tub−/−; Map1aB6) and Tub−/−; Map1aAKR mice. A representative image from one of three experiments is shown. Arrows indicate the localization of stereocilin in the stereocilia. I Quantification of stereocilin fluorescence intensity in the tallest row of stereocilia. Average fluorescent intensity was measured in 13–20 hair cells per mouse and averaged across three mice for each group. Images were analyzed using ImageJ. J Quantification of the number of the tallest stereocilia with stereocilin at their tips. Eight to ten hair cells in each mouse were counted and averaged across three mice for each group. All data are presented as means ± SEM

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