Fig. 4. Effects of soluble neuropilin/Fc reagent in collagen gel co-culture experiments. (A-D) Stage 36 DRG explants cultured with COS cell aggregates transfected with vector (VEC) alone (A) (n=25) or SEMA3A (SEMA3A) (B-D). (B) Repulsion by SEMA3A-expressing cells in the absence of neuropilin/Fc (n=14). (C) Neuropilin 1/Fc at 10 µg/ml [NP1(10)] reduces repulsion by SEMA3A (n=13); whereas (D) neuropilin 2/Fc at 10 µg/ml [NP2(10)] has little or no effect on SEMA3A-induced repulsion (n=8). (E) Histogram showing the mean repulsion score±s.e.m. Neuropilin 1 or 2/Fc does not affect axon outgrowth in co-cultures of notochord and vector-expressing cells (n=12 and 7, respectively). (F,G) Stage 36 DRG explants co-cultured with stage 17-21 notochords in the presence of (F) 3 µg/ml neuropilin 1 [NP1(3)] or (G) 10 µg/ml neuropilin 1/Fc [NP1(10)]; (n=12 for both). (H,I) Stage 36 DRG explants co-cultured with stage 17-21 notochords in the presence of (H) 3 µg/ml neuropilin 2 [NP2(3)] or (I) 10 µg/ml neuropilin 2/Fc [NP2(10)]; (n=12 and 16, respectively). (J) Histogram showing the mean repulsion score±s.e.m. (n=25 for control cultures in the absence of neuropilin/Fc). Asterisks indicate no significant repulsion, or a significant reduction in repulsion, compared to positive controls (SEMA). Scale bar: 100 µm.