Infection with lentiviruses expressing Prox1-targeting siRNA precursors si258 (lenti-si258) or si1646 (lenti-si1646) nearly obliterated endogenous Prox1 expression (Fig. 1A, top, lanes 1–3), and caused a marked increase in CYP7A1 mRNA level (Fig. 1A, bottom, bars 1–3). Here, CYP7A1 is linked to infection.