“Next, we crossed shhact/+fish with shhact/+fish carrying the epicardium-specific inducible Cre transgene Tg(tcf21:CreER) (tcf21:CreER) (Kikuchi et al., 2011) and obtained tcf21:CreER; shhact/ctembryos after PCR genotyping of individual embryos (Figure 3—figure supplement 1C).”