Fgf signaling regulates expression domains of chemokine pathway components. (A-F) The (A-C) cxcl12a and (D-F) cxcl12b genes are transcribed in regions adjacent to the dHb at 35 hpf, as shown by fluorescence in situ hybridization and immunolabeling for GFP in TgBAC(dbx1b:GFP) embryos. (G-H′) cxcl12b and (I-J′) ackr3b expression domains (brackets) are expanded in wls mutants. In fgf8a mutants, (K-L′) cxcl12b and (M-N′) ackr3b dorsal diencephalic expression domains (arrowheads) are reduced. Although the cxcl12b expression domain is reduced in (P) fgf8a mutants and expanded in (Q) wls mutants, (R) fgf8a;wls double mutants show a pattern more similar to (O) WT. Between 24 and 48 hpf, WT and wls mutant siblings were treated with either (S,S′) 0.3% DMSO, (T,T′) 18 µM SU5402+0.3% DMSO, or (U,U′) 24 µM SU5402+0.3% DMSO. Following treatment with 24 µM SU5402, cxcl12b expression in wls mutants is restored to the WT pattern (brackets). Scale bar: 30 µm. Refer to Table 1 for numerical values. Dorsal (A-G′,I,I′,K,K′,M,M′,S-U′) and lateral (H,H′,J,J′,L,L′,N,N′,O-R) views are shown. Scale bars: 50 µm.
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