Growth defects in Nfix -/- animals. Delayed weight gain and development in Nfix-/- animals. A) Reduced weight gain in Nfix -/- animals on regular chow. The weights of progeny of Nfix-/+ parents were measured and plotted according to genotype. Note that Nfix-/- animals showed a slower weight gain from ~P6 and died at ~P22 when maintained on standard lab chow. Closed circles, WT (+/+); gray circles, Nfix-/+ (HET); open circles, Nfix-/- (KO). B) Increased weight gain of Nfix -/- animals fed a soft dough diet. The cages containing litters of Nfix-/+ parents were supplemented from P10 with soft transgenic dough. Weight gain and survival were increased substantially compared to non-supplemented litters (e.g. 2A). Symbols are as in panel A. C) Delay in eyelid opening in Nfix -/- mice. Eyelid opening was measured at various times after birth in progeny of Nfix-/+ animals. Nfix-/- animals showed an ~2 day delay in eyelid opening. Closed circles, WT (+/+); closed squares, HET (Nfix-/+); open circles, KO (Nfix-/-). The numbers following the genotype indicate the number of animals analyzed. D) Delay in ear canal opening in Nfix -/- mice. The opening of the ear canal was assessed at various times after birth in progeny of Nfix-/+ animals. Nfix-/- (KO) animals showed an ~4 day delay in ear canal opening. Symbols are as in panel C. The data in panels C and D are from an ~50% mixture of dough-supplemented and non-supplemented litters.