Fig. 2

RT-PCR analysis of bmp2a (top panel) and bmp2b (middle panel) in late-stage zebrafish (5.3–5.7 mm). Column 1 contains a 100 bp ladder (New England BioLabs, Cat. No. N3231S) with 400 and 500 bp bands marked at left. Column 2 shows RT-PCR results with no template added to the reaction mix (negative control). Column 3, with 36 hpf whole embryos (Martinez-Barbera et al., 1997), and the bottom panel, with constitutively expressed ef-1α (Nordnes et al., 1994), were used as positive controls. Columns 4–9 show presence and relative levels of amplified RNA for caudal fin rays, caudal hypurals, neural and hemal arches and spines, distal anal fin fold, proximal anal fin tissue, and lens. Although bmp2a is detected by RT-PCR in caudal hypurals, this is most likely due to the presence of proximal fin ray tips, which are closely apposed to the distal hypurals. Note the absence of RNA for bmp2a and bmp2b in distal anal fin fold tissue, while proximal anal fin tissue (composed of distal radial cartilage and proximal fin ray tips) strongly expresses both genes. bmp2a levels are relatively high in the lens, bmp2b lens RNA is barely detectable.