Figure 3

RNA expression levels of the Class 3 Semaphorin receptors in the rat retina during development. Receptors: Nrp1 transcript levels are around twofold higher than the peak level of Nrp2. Co-receptors: Plxna2 had the highest peak expression levels, and L1cam the lowest. Plxna2 and Plxna3 expression levels are very similar, with Plxna2 having around fourfold higher peak levels. Nrp2: RNA levels are lowest in the embryo, rising from P7 onwards and peaking at around fourfold higher in the adult. Plxna2: Expression peaks at birth at fivefold higher than at E16, drops again by P14 and is maintained at that level into the adult. Plxna3: RNA levels increase fourfold from E16 to their peak at birth before falling back to embryonic levels by P21. Plxna4a: Expression triples from E16 to P0, doubles again at P7, falls back one third by P21 before increasing again to peak in the adult. Error bars are SEM;^* p < 0.05; n = 4–5.