PRIMPOL ensures robust handoff between on-the-fly and post-replicative DNA lesion bypass

Area of Science:

• Molecular Biology
• Genetics
• Cell Biology

Background:

• DNA replication requires damage tolerance pathways to overcome template impediments.
• PRIMPOL restarts DNA synthesis, but its integration with other damage tolerance pathways is not fully understood.
• Key pathways include REV1-dependent lesion bypass and PCNA ubiquitination-dependent gap filling.

Purpose of the Study:

• To investigate the genetic interactions of PRIMPOL with DNA damage tolerance pathways.
• To elucidate PRIMPOL's role in cell survival following disruption of REV1 and PCNA K164-dependent pathways.

Main Methods:

• Genome-wide CRISPR/Cas9 screening in a human cell line.
• Analysis of cell survival under conditions of impaired DNA damage tolerance.

Main Results:

• PRIMPOL is essential for cell survival upon loss of Y-family polymerases REV1 and POLη in a lesion-dependent manner.
• PRIMPOL broadly supports survival in cells lacking PCNA K164-dependent gap filling.
• PRIMPOL maximizes the interaction between REV1- and PCNA K164R-bypass pathways.

Conclusions:

• PRIMPOL is a critical component of DNA damage tolerance, enhancing the interplay between lesion bypass and gap filling.
• PRIMPOL-dependent repriming restricts post-replicative gap length, thereby optimizing DNA repair and cell survival.