DNA polymerase θ specializes in incorporating synthetic expanded-size (xDNA) nucleotides.
Nucleic Acids Res
; 44(19): 9381-9392, 2016 Nov 02.
Article
em En
| MEDLINE
| ID: mdl-27591252
ABSTRACT
DNA polymerase θ (Polθ) is a unique A-family polymerase that is essential for alternative end-joining (alt-EJ) of double-strand breaks (DSBs) and performs translesion synthesis. Because Polθ is highly expressed in cancer cells, confers resistance to ionizing radiation and chemotherapy agents, and promotes the survival of homologous recombination (HR) deficient cells, it represents a promising new cancer drug target. As a result, identifying substrates that are selective for this enzyme is a priority. Here, we demonstrate that Polθ efficiently and selectively incorporates into DNA large benzo-expanded nucleotide analogs (dxAMP, dxGMP, dxTMP, dxAMP) which exhibit canonical base-pairing and enhanced base stacking. In contrast, functionally related Y-family translesion polymerases exhibit a severely reduced ability to incorporate dxNMPs, and all other human polymerases tested from the X, B and A families fail to incorporate them under the same conditions as Polθ. We further find that Polθ is inhibited after multiple dxGMP incorporation events, and that Polθ efficiency for dxGMP incorporation approaches that of native dGMP. These data demonstrate a unique function for Polθ in incorporating synthetic large-sized nucleotides and suggest the future possibility of the use of dxG nucleoside or related prodrug analogs as selective inhibitors of Polθ activity.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
DNA
/
DNA Polimerase Dirigida por DNA
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Replicação do DNA
Limite:
Humans
Idioma:
En
Ano de publicação:
2016
Tipo de documento:
Article