Movie 4.

The beating heart of a Xenopus embryo injected with fbrsl1 tb MO. Four-cell-stage embryos were injected in one dorsal blastomere with 7.5 ng fbrsl1 tb MO in combination with 50 pg mGFP RNA as a lineage tracer. The embryos were anesthetized in 0.1x MBS (modified Barth's saline) containing 0.01% benzocaine. Beating hearts were recorded at stage 44. A representative embryo is shown from the ventral side. The heart is severely malformed and the blood flow is not visible.