A nuclear family A DNA polymerase from Entamoeba histolytica bypasses thymine glycol.
BACKGROUND
Eukaryotic family A DNA polymerases are involved in mitochondrial DNA replication or translesion DNA synthesis. Here, we present evidence that the sole family A DNA polymerase from the parasite protozoan E. histolytica (EhDNApolA) localizes to the nucleus and that its biochemical properties indicate that this DNA polymerase may be involved in translesion DNA synthesis.


RESULTS
EhDNApolA is the sole family A DNA polymerase in E. histolytica. An in silico analysis places family A DNA polymerases from the genus Entamoeba in a separate branch of a family A DNA polymerases phylogenetic tree. Biochemical studies of a purified recombinant EhDNApolA demonstrated that this polymerase is active in primer elongation, is poorly processive, displays moderate strand displacement, and does not contain 3'-5' exonuclease or editing activity. Importantly, EhDNApolA bypasses thymine glycol lesions with high fidelity, and confocal microscopy demonstrates that this polymerase is translocated into the nucleus. These data suggest a putative role of EhDNApolA in translesion DNA synthesis in E. histolytica.


CONCLUSIONS
This is the first report of the biochemical characterization of a DNA polymerase from E. histolytica. EhDNApolA is a family A DNA polymerase that is grouped into a new subfamily of DNA polymerases with translesion DNA synthesis capabilities similar to DNA polymerases from subfamily nu.
Pastor-Palacios
Guillermo
G
Laboratorio Nacional de Genómica para la Biodiversidad, CINVESTAV, Irapuato, México.
Azuara-Liceaga
Elisa
E
Brieba
Luis G
LG
D002467:Cell Nucleus / Q000737:chemistry; D004258:DNA Polymerase III / Q000302:isolation & purification / Q000378:metabolism*; D004748:Entamoeba histolytica / Q000201:enzymology*; D008958:Models, Molecular; D010802:Phylogeny; D017434:Protein Structure, Tertiary; D015800:Protozoan Proteins / Q000302:isolation & purification / Q000378:metabolism*; D011994:Recombinant Proteins / Q000302:isolation & purification / Q000378:metabolism; D017385:Sequence Homology; D013941:Thymine / Q000031:analogs & derivatives* / Q000378:metabolism
D015800:Protozoan Proteins; D011994:Recombinant Proteins; C029389:thymine glycol; C065639:DNA polymerase A; D004258:DNA Polymerase III; D013941:Thymine