Expression of klf2b in the developing pectoral fins of the zebrafish.

Whole-mount in situ hybridization of dissected zebrafish pectoral fins with riboprobe for the zebrafish klf2b gene. Fins are shown with distal up and anterior margin to the left; scale bar is 50 μm. (A) klf2b is expressed in the central mesenchymal region of the fin bud at 2 days past fertilization (dpf). (B) Expression is restricted to distal positions of the fin bud at 3 dpf. (C) At 4 dpf, a narrow row of klf2b-expressing cells lines the distal end of the muscular compartment of the fin (arrowheads). (D) By 5 dpf, only scattered cells in the overlying epidermis expressklf2b (arrows). Original magnification 200 ×; stained with NBT/BCIP precipitate.