Figure 5.
Cells from Ubr3-knockout mice contain elevated levels of APE1 protein. (A and B) Whole cell extracts from MEFs from several wild-type (WT), Ubr3-knockout (KO) and heterozygous mice (HET) were prepared and analysed by 10% SDS–PAGE and immunoblotting using the indicated antibodies (C) Wild-type and Ubr3-knockout MEFs cells were grown on 10-cm2 dishes for 24 h to 70–80% confluency and then transfected with equal amounts of mouse Flag-tagged APE1 (APEXFlag) expression plasmid. After 24 h, cells were pelleted by centrifugation, whole cell extracts were prepared and analysed by 10% SDS–PAGE and western blotting with the antibodies indicated. (D) RNA was prepared from wild-type and Ubr3-knockout MEFs and the levels of APE1, UBR3 and actin mRNA analysed by RT–PCR.