title: DNA base excision repair in human malaria parasites is predominantly by a long-patch pathway.
abstract: Mammalian cells repair apurinic/apyrimidinic (AP) sites in DNA by two distinct pathways: a polymerase beta (pol beta)-dependent, short- (one nucleotide) patch base excision repair (BER) pathway, which is the major route, and a PCNA-dependent, long- (several nucleotide) patch BER pathway. The ability of a cell-free lysate prepared from asexual Plasmodium falciparum malaria parasites to remove uracil and repair AP sites in a variety of DNA substrates was investigated. We found that the lysate contained uracil DNA glycosylase, AP endonuclease, DNA polymerase, flap endonuclease, and DNA ligase activities. This cell-free lysate effectively repaired a regular or synthetic AP site on a covalently closed circular (ccc) duplex plasmid molecule or a long (382 bp), linear duplex DNA fragment, or a regular or reduced AP site in short (28 bp), duplex oligonucleotides. Repair of the AP sites in the various DNA substrates involved a long-patch BER pathway. This biology is different from mammalian cells, yeast, Xenopus, and Escherichia coli, which predominantly repair AP sites by a one-nucleotide patch BER pathway. The apparent absence of a short-patch BER pathway in P. falciparum may provide opportunities to develop antimalarial chemotherapeutic strategies for selectively damaging the parasites in vivo and will allow the characterization of the long-patch BER pathway without having to knock-out or inactivate a short-patch BER pathway, which is necessary in mammalian cells.
authors.affiliation: Department of Microbiology, Thomas Jefferson University, 1020 Locust St., Philadelphia, Pennsylvania 19107, USA.
authors.forename: B M
authors.initials: BM
authors.lastname: Haltiwanger
authors.forename: Y
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: E
authors.initials: E
authors.lastname: Nicolas
authors.forename: G L
authors.initials: GL
authors.lastname: Dianov
authors.forename: V A
authors.initials: VA
authors.lastname: Bohr
authors.forename: T F
authors.initials: TF
authors.lastname: Taraschi
mesh_terms: D000818:Animals; D001665:Binding Sites / Q000235:genetics; D019757:Carbon-Oxygen Lyases / Q000378:metabolism; D002474:Cell-Free System / Q000201:enzymology; D045647:DNA Glycosylases; D004260:DNA Repair; D004270:DNA, Circular / Q000378:metabolism; D016054:DNA, Protozoan / Q000378:metabolism*; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase; D043223:Deoxyribonuclease IV (Phage T4-Induced); D004706:Endodeoxyribonucleases / Q000378:metabolism; D004789:Enzyme Activation; D029968:Escherichia coli Proteins; D045585:Flap Endonucleases; D006801:Humans; D016778:Malaria, Falciparum / Q000201:enzymology / Q000235:genetics / Q000469:parasitology; D009699:N-Glycosyl Hydrolases / Q000378:metabolism; D010957:Plasmids / Q000378:metabolism; D010963:Plasmodium falciparum / Q000201:enzymology / Q000235:genetics*; D051981:Uracil-DNA Glycosidase
chemical_list: D004270:DNA, Circular; D016054:DNA, Protozoan; D029968:Escherichia coli Proteins; D004706:Endodeoxyribonucleases; D045585:Flap Endonucleases; C468317:FEN1 protein, human; D043223:Deoxyribonuclease IV (Phage T4-Induced); C468972:endonuclease IV, E coli; D045647:DNA Glycosylases; D009699:N-Glycosyl Hydrolases; D051981:Uracil-DNA Glycosidase; D019757:Carbon-Oxygen Lyases; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase