FIG. 1.

Neogenin is upregulated in the absence of Rb in the developing forebrain. (A) In the absence of Rb (Foxg1-Cre/+; Rb^loxP/loxP) increased neogenin expression is detected in the subventricular zone, cortex, and striatum compared with results in controls (Foxg1-Cre/+; Rb^loxP/+). In situ hybridizations were performed on three or more independent samples for DCC, RGMa, netrin-1, and neogenin. Arrows indicate regions of overlapping expression between neogenin and netrin-1 in the ganglionic eminence. (B) Western blot analysis was performed on neural precursor cells isolated from E14.5 Rb conditional mutants and control embryos. Note efficient recombination of the floxed Rb allele, showing no detectable Rb. Rb mutants showed an upregulation of neogenin compared to levels in the control. Densitometric quantification of neogenin expression detected by Western blotting was performed using ImageJ analysis of three independent experiments. Significance was determined through a paired two-tailed t test for the control and conditional Rb mutant (P < 0.05).