Figure 7

Gpc1 phenotypes require Fgf17. Compound Gpc1/Fgf17 genotypes were produced by interbreeding Gpc1^+/-;Fgf17^+/- mice. (A-E) Nissl-stained mid-sagittal sections through the cerebella of adult compound mutants. Red arrowheads mark the anterior-most lobe (lobe I), which disappears in both Gpc1^-/- and Fgf17^-/- animals. Red arrows mark the fusion of lobes III and IV, a phenotype observed in Fgf17^-/- mice. Note that the Gpc1^-/-;Fgf17^-/- phenotype is no more severe than the single Fgf17^-/- phenotype. (F) Fresh brain weights of adult compound mutants. Genotypes for each category are as indicated; 'N' refers to the number of animals obtained of each genotype. The data show that, on their own, the presence of either one or two copies of mutant alleles for either Gpc1 or Fgf17 progressively reduces brain size. When animals are null for Fgf17, the presence of mutant Gpc1 alleles has no significant effect (*P < 0.005; **P < 0.001; by Student's t-test).