PrimPol-A new polymerase on the block.

The DNA-directed primase-polymerase PrimPol of the archaeo-eukaryotic primase superfamily represents an ancient solution to the many problems faced during genome duplication. This versatile enzyme is capable of initiating de novo DNA/RNA synthesis, DNA chain elongation, and has the capacity to bypass modifications that stall the replisome by trans-lesion synthesis or origin-independent re-priming, thus allowing discontinuous synthesis of the leading strand. Recent studies have shown that PrimPol is an important new player in replication fork progression in eukaryotic cells; this review summarizes our current understanding of PrimPol and highlights important questions that remain to be addressed.