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Fig. 3. Notch signalling regulates pronephric wnt4 expression. (A-D) X. laevis embryos were injected as previously described, with mRNA co-injected with beta-galactosidase mRNA to act as a lineage tracer (red staining on the injected side). Embryos were cultured to stage 28 when wnt4 (A,B), delta1 (C) and serrate1 (D) expression was detected by in situ hybridisation. Mis-activation of Notch signalling by injection of notch-ICD mRNA causes ectopic wnt4 expression (white arrow, A), whereas deltaSTU mRNA inhibits wnt4 expression (B). wnt4 overexpression does not have an effect on delta1 or serrate1 expression levels (B). Expression of both these genes is altered in the anteroposterior register; frequently, expression is more distal (white brackets) and rarely ectopic (white arrow, C). Asterisk denotes injected side. |
