To investigate the hepatic function of Y67-FXR phosphorylation, FXR was specifically knocked out in the livers of FXR floxed mice by infection of AAV-TBG-Cre and either FXR-WT or p-defective Y67F-FXR mutant was expressed by co-injection of AAV-TBG viruses for each (Fig. 2a). Here, NR1H4 is linked to infection.