Fig. 2. Expression pattern of Nematostella FGFa, FGFb and FGFRa. (A) Temporal expression profile determined by RT-PCR; NvFGFa1 is not expressed maternally. ooc, unfertilised eggs; blast, blastula (12 hpf); gastr, gastrulation (24 hpf); e.plan, early planula (48 hpf); l.plan, late planula (96 hpf); pp, primary polyp (7 dpf). (B-S) Spatial expression pattern determined by in situ hybridisation. Lateral views, blastoporus/mouth to the right, apical pole and swimming direction of planula larvae to the left. (B-E) NvFGFa2, (F-I) NvFGFa1, (J-M) NvFGFRa. (B,F,J) Gastrula, (C,G,K) early planula, (D,H,L) late planula, (E,I,M) primary polyp. (N-S) Fluorescent double in situ hybridisation at late gastrula stage with indicated probes. The NvFGFa1 and NvFGFa2 expression domains are identical; the NvFGFRa expression domain is wider than that of NvFGFa2 (and NvFGFa1).