PrimPol bypasses UV photoproducts during eukaryotic chromosomal DNA replication

Area of Science:

• Molecular Biology
• Genetics
• Biochemistry

Background:

• DNA replication is essential for genomic stability.
• Replication fork stalling due to DNA damage necessitates specialized repair mechanisms.
• The enzymes involved in completing DNA replication on damaged templates are not fully identified.

Purpose of the Study:

• To investigate the role of Primase-Polymerase (PrimPol) in eukaryotic chromosomal DNA replication.
• To determine PrimPol's involvement in bypassing DNA lesions during replication.
• To elucidate PrimPol's contribution to genomic stability and cellular survival.

Main Methods:

• Functional assays to assess replication fork progression on damaged DNA templates.
• Analysis of PrimPol's translesion synthesis (TLS) capabilities.
• Epistasis analysis with known DNA repair pathways, including Pol η.
• Assessment of UV-induced cytotoxicity in cells lacking PrimPol function.

Main Results:

• Primase-Polymerase (PrimPol) is essential for replication fork progression on UV-damaged DNA.
• PrimPol catalyzes translesion synthesis (TLS) to bypass UV lesions.
• The PrimPol-mediated UV lesion bypass pathway is distinct from the Pol η pathway.
• PrimPol protects xeroderma pigmentosum variant (XP-V) cells from UV cytotoxicity.
• PrimPol is also required for efficient replication during unperturbed S phase.

Conclusions:

• PrimPol plays a significant role in maintaining replication fork progression in eukaryotic cells.
• PrimPol functions as a key enzyme in DNA damage tolerance pathways.
• PrimPol contributes to genomic stability by facilitating replication through damaged DNA.