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Figure 6
RA can promote notochord sheath mineralization independently of BMP signaling at later stages of vertebral column formation. (A–D) Blockage of BMP signaling with synchronous activation of the RA pathway from six to eight dpf results in larvae with less severe disrupted notochord sheath mineralization while chordoblasts show clear marks of RA responsiveness (decreased Tg(R2-col2a1a:egfp) activity and less distinct cellular morphology). Lateral views of transgenic zebrafish larvae shown in merged transmitted and fluorescent light channels with tissue staining, genotypes and treatments as indicated at an age of 8dpf (A–D). Heat-shocks were performed once a day for 45 minutes at 40°C. Arrows in (D) point at zones of ectopic mineralization. Scale bars: 150 µm.