Spontaneous mutagenesis in human cells is controlled by REV1-Polymerase ζ and PRIMPOL

Area of Science:

• Molecular Biology
• Genetics
• Genomics

Background:

• Translesion DNA synthesis (TLS) is crucial for replicating damaged DNA using specialized polymerases.
• Key regulators of TLS include REV1, PCNA ubiquitylation, and PRIMPOL, which control polymerase recruitment and gap formation.

Purpose of the Study:

• To investigate the impact of TLS control mechanisms (REV1, PCNA ubiquitylation, PRIMPOL) on spontaneous mutagenesis.
• To elucidate the specific roles of these mechanisms in different types of DNA mutations, including base substitutions and deletions.

Main Methods:

• Whole-genome sequencing of cultured human RPE-1 cell clones with genetic modifications.
• Analysis of spontaneous mutagenesis in REV1, PCNA, and PRIMPOL deficient/mutant cell lines.

Main Results:

• REV1 and Polymerase ζ are essential for a significant component of base substitution mutagenesis.
• PRIMPOL deficiency reduces a component of mutagenesis resembling oxidative damage.
• REV1, PCNA, and REV3L mutants exhibit various deletions, indicating alternative TLS pathways and potential for chromosomal instability.

Conclusions:

• TLS plays a dual role: protecting the genome from deletions and large rearrangements while driving the majority of spontaneous base substitutions.
• Understanding TLS regulation is critical for comprehending genome stability and mutagenesis.