Disruption of DNA polymerase ζ engages an innate immune response

Area of Science:

• Molecular Biology
• Genetics
• Immunology

Background:

• DNA polymerase ζ (pol ζ) is crucial for genomic stability in mammalian cells.
• Rev3l, the catalytic subunit of pol ζ, is essential; its disruption causes toxicity and DNA damage, including micronuclei formation.
• The consequences of this genomic stress on cellular pathways were previously unknown.

Purpose of the Study:

• To investigate the transcriptomic changes in pol ζ-defective cells.
• To identify the molecular pathways activated by the disruption of pol ζ.
• To explore the potential therapeutic implications of these findings.

Main Methods:

• RNA sequencing (RNA-seq) was employed to analyze the transcriptome of Rev3l-disrupted cells.
• Quantitative PCR and Western blotting were used to validate gene and protein expression changes.
• The role of the cGAS-STING pathway in mediating the observed immune response was assessed.

Main Results:

• Disruption of Rev3l altered the expression of 1,117 transcripts (≥4-fold change).
• Transcriptomic patterns indicated an induction of the innate immune response, specifically interferon-stimulated genes (ISGs), at both mRNA and protein levels.
• The cGAS-STING pathway was identified as the driver of ISG induction in pol ζ-defective cells.
• Elevated expression of interferon-stimulated chemokines was observed in Rev3l-disrupted mouse skin cells.

Conclusions:

• Disruption of pol ζ leads to significant genomic stress and activates the innate immune system through the cGAS-STING pathway.
• These findings suggest that pol ζ deficiency may increase sensitivity to genotoxins.
• Targeting pol ζ could offer a dual therapeutic benefit in cancer treatment by increasing genotoxin sensitivity and engaging innate immunity.