DNA polymerase

Epigenetics

Molecular biology

DNA repair

Base excision repair

PARP1

Polymerase

DNA damage

Biology

Gene

Poly ADP ribose polymerase

Cell biology

DNA replication

Genetics

Trends in Cell Biology

DNA single-strand breaks (SSBs) are amongst the commonest DNA lesions arising in cells, with many tens of thousands induced in each cell each day. SSBs arise not only from exposure to intracellular and environmental genotoxins but also as intermediates of normal DNA metabolic processes, such as the removal of torsional stress in DNA by topoisomerase enzymes and the epigenetic regulation of gene expression by DNA base excision repair (BER). If not rapidly detected and repaired, SSBs can result in RNA polymerase stalling, DNA replication fork collapse, and hyperactivation of the SSB sensor protein poly(ADP-ribose) polymerase 1 (PARP1).

DNA single-strand break repair and human genetic disease