Figure 6.

Disruption of Dhx9 in mice causes behavioral and neurological abnormalities

(A–C) Dhx9^−/− mice were hypoactive in response to a novel environment (A: decreased distance traveled; B: decreased speed) in an open field and to decreased rearing (C) upon the first introduction to a novel home cage. However, male Dhx9^−/− mice showed more rearing activity with lights off during the active phase in the home cage. This increased vertical activity was evident in both male and female Dhx9^−/− mice in the latter half of the active phase. Shaded areas encompass the period between lights off and lights on (18:00–06:00) and represent the mean ± SEM.

(D and E) Both 2-paw and 4-paw grip strength were reduced in Dhx9^−/− mice (D). Lower grip strength was predicted by the lower body weight in linear regression analysis (E).

(F) 20% of Dhx9^−/− mice showed tremors in the SHIRPA analysis.

(G and H) Both an absent auditory response curve in the auditory brainstem response (G) and decreased acoustic startle reactivity (H) indicated deafness in Dhx9^−/− mice.

(I–K) The body weight of Dhx9^−/− mice was lower than that of WT mice (I). Dhx9^−/− mice had lower cumulative food intake and lost more weight over a 21 h period than WT mice after transferring to a new home cage. #p < 0.05, male +/+ vs. −/−; ^∗p < 0.05, ^∗∗p < 0.01, ^∗∗∗p < 0.001, ^∗∗∗∗p < 0.0001, +/+ vs. −/−. Data represent the mean ± SD.