Fig 1: Identification of nuclear UNG1. (A) Western blot analysis of whole cell and nuclear extracts derived from CH12F3 clones. The mitochondrial protein MRPL11 (mitochondrial ribosomal protein L11, 39S subunit component) was used to validate the purity of the nuclear extracts. Equal amounts (total protein) are loaded in each lane. (B) Relative quantification of UNG isoform variants (UNG1/UNG2) in CH12F3 whole cell extracts (WCE) and nuclear extracts (NuE). The UNG1/UNG2 ratios in the different extracts from WT and Int2 clones were quantified from western blots. The bars represent the mean value of 5–6 biological replicates. Error bars are indicated. Two forms of UNG1 were observed in WCE, named UNG1-HMW (higher molecular weight) and UNG1-LMW (lower molecular weight). Western blots of UNG isoforms in WCE and nuclear extract derived from CH12F3 WT cells are shown below the bar diagram. (C) Naïve B cells were isolated from spleen, seeded (2 × 106/ml), and stimulated with IL4 and LPS for 48 h before harvest and generation of whole cell extract (WCE) and nuclear extracts (NuE). UNG isoform variants were detected by western blot analysis. (D) Western blot analysis of UNG isoforms in several mouse cell lines (NIH3T3, JC and JMT-93). (E) Representative confocal image of live cells (HeLa) co-expressing mUNG1-CFP, mUNG2-YFP and Cherry-PCNA.