A previous study reported that the expression of Hh ligand genes, dhh and ihhb, is upregulated in injured zebrafish hearts (Wang J, et al. Nature 2015). Consistent with this result, our new semi-qRT-PCR result revealed the upregulation of dhh and ihhb expression in purified epicardial cells after injury (Figure 5B). The expression of these genes was unchanged after the inactivation of shha expression (Figure 5C). Figure 5B and 5C have been modified to include these results in the revised manuscript. The other Hh ligand genes shhb and ihha were undetectable, as previously reported (Wang J, et al. Nature 2015). Thus, the redundant Hh proteins present in injured zebrafish hearts are likely Dhh and Ihhb, and these ligands are expressed at least in the epicardium.