FOXA1 and cystic fibrosis: On the other hand, the expression levels of the transcripts encoding Forkhead Box A1 (FOXA1) and Hepatocyte Nuclear Factor 4α (HNF4α), two major transcriptional regulators of liver differentiation, in the livers of CF rabbits were comparable to those in the WT rabbits (Fig. S9C), which indicates that CFTR deficiency does not significantly affect the liver development.