First Author | Marini F | Year | 2003 |
Journal | J Biol Chem | Volume | 278 |
Issue | 34 | Pages | 32014-9 |
PubMed ID | 12794064 | Mgi Jnum | J:85120 |
Mgi Id | MGI:2672148 | Doi | 10.1074/jbc.M305646200 |
Citation | Marini F, et al. (2003) POLN, a nuclear PolA family DNA polymerase homologous to the DNA cross-link sensitivity protein Mus308. J Biol Chem 278(34):32014-9 |
abstractText | The Drosophila Mus308 gene is unusual in encoding both a family A DNA polymerase domain and a DNA/RNA helicase domain. A mus308 mutation was shown to result in increased sensitivity to DNA cross-linking agents, leading to the hypothesis that Mus308 functions in the repair of DNA interstrand cross-links. Recently a mammalian ortholog of Mus308, POLQ, has been identified. We report here the identification, cloning, and characterization of POLN and its gene product, a new mammalian DNA polymerase also related to Mus308. The human cDNA encodes a protein of 900 amino acid residues. The region starting from residue 419 shares 33% identity (48% similarity) with the equivalent region of Escherichia coli DNA polymerase I. POLN is expressed in human cell lines with numerous alternatively spliced transcripts, and a full-length human coding region that comprises 24 exons within 160 kilobases of genomic DNA. Expression analysis by northern blotting and in situ hybridization showed highest expression of full-length POLN in human and mouse testis. POLN localized to the nucleus when expressed as a enhanced green fluorescent protein (GFP)-tagged protein in human fibroblasts. GFP-tagged recombinant POLN had DNA polymerase activity on activated calf thymus DNA and on a singly primed template. |