Figure 5

RNA expression levels of the Class 3 Semaphorin receptors in the rat superior colliculus during development. Receptors: Nrp1 and Nrp2 share similar expression profiles, with peaks around E19 and birth and then falling away into the adult. Co-receptors: All co-receptors bar L1cam follow the same expression profile, peaking at E19 before falling after birth and into the adult. Plxna1 and Plxna3 are the predominant transcripts. Nrp1: Peak RNA expression is at E19, falling threefold by P7 and maintained into the adult. Nrp2: Transcript levels double from E16 to P0, with high variability at E19. Expression falls from P0 to P7 and is maintained at around half peak levels in the adult. Plxna1: RNA levels are highly variable at E16 and E19 where they peak. From birth expression levels are halved, continue to decline up to P21 where they are sevenfold lower than at peak, and this level is maintained into the adult. Plxna2: RNA levels are highly variable at E16 and E19 where they peak. Expression drops threefold by P7 and is maintained into the adult. Plxna3: RNA levels are highly variable at E16 and E19 where they peak. Expression falls to half peak at P7, one quarter peak at P14 and is sevenfold lower than peak by P21 and in the adult. Plxna4a: RNA levels are highly variable at E16 and E19 where they peak before falling fourfold by P7 and into the adult. Error bars are SEM; * p < 0.05; n = 4–5.