FIG. 2.

Exons 4 and 5 are deleted efficiently and specifically in the livers of H4LivKO mice. (A) Time course of Cre-mediated recombination at the HNF4α locus. Liver RNA from H4LivKO and control animals was subjected to Northern blotting and probed with a fragment of the HNF4α cDNA derived from the targeted exons (exons 4 and 5). (B to D) Tissues were isolated from 45-day-old wild-type (HNF4α +/+; AlbCre −/−), AlbCre (HNF4α +/+; AlbCre +/−), H4LivKO (HNF4α fl/fl; AlbCre +/−), and H4Flox (HNF4α fl/fl; AlbCre −/−) mice. (B) Northern blot analysis of 10 μg of total liver RNA. A truncated RNA species is evident in livers of H4LivKO mice; this species hybridizes to a 3′ fragment of the HNF4α cDNA but fails to hybridize to exons 4 and 5. (C) Western blot analysis of liver nuclei. Twenty micrograms of total nuclear protein was separated on a sodium dodecyl sulfate–10% polacrylamide gel electrophoresis gel and transferred to nitrocellulose. The membrane was probed with an antibody raised to a C-terminal peptide of HNF4α (Santa Cruz Biotechnology). Equal loading of nuclear protein was demonstrated by reprobing the membrane with an antibody directed against mouse histone H1. No full-length or truncated HNF4α protein was detected in livers of H4LivKO mice. (D) Northern blot analysis of total RNA isolated from control tissues of H4LivKO and control animals.