XB-IMG-47810
Xenbase Image ID: 47810
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Figure 3. Effects of expressing truncated EphA4 and EphB1 on third arch neural crest. RNA encoding truncated EphB1 (a), EphA4, (b,e) or a mixture of these RNAs (c,f,h–l) was microinjected into one cell of two-cell stage Xenopus embryos. The embryos were allowed to develop to stage 21 (a–c), or stages 23–25 (d–l), then fixed and in situ hybridisation carried out. (a–c) Dorsal views of flat mounted embryos, with the injected side to the right in (a,b), and on the left in (c). (d,g) Uninjected side of injected embryos. (e,f,h–l) Injected side of embryos. Krox-20 gene expression was detected as a marker of third arch neural crest (a–f), Krox-20 plus EphA2 (Eck) to detect third arch (stronger signal) plus second arch (weaker signal) neural crest (g–i), or EphA2 alone (j). Krox-20-expressing neural crest cells were observed in ectopic locations; the extent of this disruption varied between embryos within an experiment and between different batches of embryos. To further analyse whether second arch neural crest was affected in embryos in which third arch crest migration was disrupted, DIG-labelled EphA2 probe (k) then fluorescein-labelled Krox-20 probe (l) were detected sequentially. The second arch stream is normal, but ectopic caudal third arch crest cells are detected; the appearance of this embryo has changed due to loss of pigmentation during processing. The white arrows indicate a normal restricted stream of third arch (n3) and second arch (n2) neural crest, and the black arrows indicate cells present in abnormal locations. Image published in: Smith A et al. (1997) Copyright © 1997. Image reproduced with permission of the Publisher, Elsevier B. V.
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