Figure 1. Restoring Lrp4 expression selectively in muscle of Lrp4 mutant mice rescues neonatal lethality.
(A) Lrp4−/−; Lrp4m mice are fertile and live a normal lifespan. (B) The body mass of six-week old Lrp4−/−; Lrp4m mice is reduced by 16% (wild-type, 21.4 ± 0.8 g, n = 10; Lrp4−/−; Lrp4m, 18.0 ± 0.5 g, n = 5). (C) The gross morphology of the adult brain is similar in wild-type and Lrp4−/−; Lrp4m mice. (D) The size of the adult brain is reduced by 11% in Lrp4−/−; Lrp4m mice (wild-type, 0.45 ± 0.005 g, n = 17; Lrp4−/−; Lrp4m, 0.4 ± 0.008 g, n = 15). (E, F, G) The locomotor activity of Lrp4−/−; Lrp4m mice in an open field test was normal as measured by distance traveled (E), mean velocity (F), and maximum velocity (G) (wild-type, n = 17; Lrp4−/−; Lrp4m, n = 15). (H) Lrp4−/−; Lrp4m mice showed reduced exploratory behavior (wild-type, 22.3 ± 2.2%, n = 29; Lrp4−/−; Lrp4m, 14.9 ± 1.2%, n = 25). (I) Representative heat maps of wild-type and Lrp4−/−; Lrp4m mice during a 30 min open field test.