As LGR5 is required for efficient CM differentiation in hPSCs (Jha et al., 2017; Sahara et al., 2019), we hypothesized that infection with a doxycycline (DOX)-inducible LGR5-expressing lentivirus might rescue the cardiac defects in GATA6-/- hESCs. Here, GATA6 is linked to infection.