title: PPL2 translesion polymerase is essential for the completion of chromosomal DNA replication in the African trypanosome.
abstract: Faithful copying of the genome is essential for life. In eukaryotes, a single archaeo-eukaryotic primase (AEP), DNA primase, is required for the initiation and progression of DNA replication. Here we have identified additional eukaryotic AEP-like proteins with DNA-dependent primase and/or polymerase activity. Uniquely, the genomes of trypanosomatids, a group of kinetoplastid protozoa of significant medical importance, encode two PrimPol-like (PPL) proteins. In the African trypanosome, PPL2 is a nuclear enzyme present in G2 phase cells. Following PPL2 knockdown, a cell-cycle arrest occurs after the bulk of DNA synthesis, the DNA damage response is activated, and cells fail to recover. Consistent with this phenotype, PPL2 replicates damaged DNA templates in vitro, including templates containing the UV-induced pyrimidine-pyrimidone (6-4) photoproduct. Furthermore, PPL2 accumulates at sites of nuclear DNA damage. Taken together, our results indicate an essential role for PPL2 in postreplication tolerance of endogenous DNA damage, thus allowing completion of genome duplication.
authors.affiliation: Genome Damage and Stability Centre, University of Sussex, Brighton BN1 9RQ, UK.
authors.forename: Sean G
authors.initials: SG
authors.lastname: Rudd
authors.forename: Lucy
authors.initials: L
authors.lastname: Glover
authors.forename: Stanislaw K
authors.initials: SK
authors.lastname: Jozwiakowski
authors.forename: David
authors.initials: D
authors.lastname: Horn
authors.forename: Aidan J
authors.initials: AJ
authors.lastname: Doherty
mesh_terms: D000595:Amino Acid Sequence; D002875:Chromosomes / Q000235:genetics; D017124:Conserved Sequence; D004249:DNA Damage; D017931:DNA Primers / Q000235:genetics / Q000378:metabolism; D004260:DNA Repair; D004261:DNA Replication; D016054:DNA, Protozoan / Q000235:genetics; D004259:DNA-Directed DNA Polymerase / Q000235:genetics / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D008969:Molecular Sequence Data; D021381:Protein Transport; D015800:Protozoan Proteins / Q000235:genetics / Q000378:metabolism*; D014346:Trypanosoma brucei brucei / Q000201:enzymology* / Q000235:genetics
chemical_list: D017931:DNA Primers; D016054:DNA, Protozoan; D015800:Protozoan Proteins; D004259:DNA-Directed DNA Polymerase