FIGURE 1.

UHRF1 knock-out ES cells have global loss of DNA methylation. a, exon structure of the mouse Uhrf1 gene is shown. β-geo represents the insertion of gene-trap vectors. b, cell lysates from WT and Uhrf1 knock-out (KO) ES cells were immunoblotted (IB) with anti-mouse UHRF1 antibody. The upper band represents the fusion product of the nonfunctional N terminus of UHRF1 and the β-geo cassette in the gene-trap vector. Actin was used as a loading control. c, genomics DNA from WT and Uhrf1 knock-out ES cells were digested with HpaII and separated by agarose gel electrophoresis. d, Southern blotting was performed using the gel in c, and the membrane was blotted using a minor satellite probe.