Fig. 2.

Effects of PS1 and PS2 transgenes on the abnormal skeletal morphology present in PS1-hypomorphs. All animals shown are homozygous for the hypomorphic PS1 allele. Row 1 shows an animal with no superimposed transgene, whereas rows 2–6 represent animals with superimposed transgenes expressing mutant PS1, wtPS2, mutant PS2, or wt APP transgenes (as indicated). The disorganized and reduced number of vertebrae (10) and reduced number of ribs, fusion of ribs (arrow), and aberrant tail morphology present in PS1-null homozygotes is remedied by mutant PS1 and PS2 transgenes (these mice have 13 normal thoracic vertebrae and ribs) but not by a TgAPP695.6209 transgene (46) nor by the wt PS2 transgene (only 10–11 ribs, with the last 4 ribs partially detached).