Fig. 5

Some neuronal defects in cntn2 morphants are likely to be off-target effects.

(A) Experiments to distinguish between genetic compensation in MZcntn2−/− mutants, and off-target effects of the cntn2 MO. Normal development of FBM and nucMLF neuron in MZcntn2−/− mutants injected with cntn2 MO would suggest compensation. However, defective development of both cell types in these embryos would suggest off-target effects. (B, D, F, H) Dorsal views of the hindbrain with anterior to the left. Tg(isl1:gfp) embryos were fixed at 48 hpf, and processed for immunohistochemistry with zn5 antibody (red) to label hindbrain commissural neurons and axons at rhombomere boundaries, and anti-GFP antibody (green) to label FBM neurons (arrowheads). (B, D) FBM neurons migrate normally in control MO-injected cntn2+/+ (B) and in MZcntn2−/− (D) embryos. (F, H) Migration of FBM neurons is greatly reduced in cntn2 MO-injected cntn2+/+ (F) and MZcntn2−/− (H) embryos. (C, E, G, I) Ventral views of the midbrain, with anterior to the left, of Tg(pitx2c:gfp) embryos labeled with anti-GFP antibody. (C, E) Normal nucMLF development in control MO-injected cntn2+/+ (C) and MZcntn2−/− (E) embryos. (G, I) Defective nucMLF development in cntn2 MO-injected cntn2+/+ (G) and MZcntn2−/− (I) embryos. (J) Quantification of data presented in B, D, F and H. Number in parenthesis denotes number of embryos. (K) Quantification of data presented in C, E, G and I. Number in parenthesis denotes number of embryos. Scale bar in B, 50 μm for B, D, F, and H; Scale bar in F, 50 μm for C, E, G, and I. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)