Fig. 1. Tg737^orpk mutant mice develop hydrocephalus. (A) Comparison of lateral views of 10-day-old wild-type and Tg737^orpk mice indicates that the mutants exhibit a bulging forehead (arrow), characteristic of hydrocephalus. (B) Gross analysis of the brains from mutants shows signs of compression at the olfactory bulb and the frontal pole of the cerebrum (black arrowhead). Also, the cerebellum is more prominent in mutant animals (white arrowhead) than in the wild-type control. (C) Hematoxylin and Eosin-stained coronal sections through identical regions of the brain demonstrate marked dilatation of the lateral ventricles (arrows) in mutant animals compared with wild-type controls. Scale bar: 4 mm.