JAG1 and cholestasis: To investigate which liver cell populations are affected by Jag1 loss of function at the onset of cholestasis, we first analyzed Jag1+/+, Jag1Ndr/+, and Jag1Ndr/Ndr livers with single-cell RNA sequencing (scRNA seq) at embryonic day (E) 16.5 and postnatal day 3 (P3) (Fig. 2A).