POLQ suppresses genome instability and alterations in DNA repeat tract lengths

Area of Science:

• Genetics
• Molecular Biology
• Cancer Research

Background:

• DNA polymerase theta (POLQ) is crucial for the alternative non-homologous end-joining (ANHEJ) DNA repair pathway.
• POLQ ligates DNA double-strand breaks, playing a role in maintaining genome integrity.

Purpose of the Study:

• To investigate the role of POLQ in telomere crisis and genome stability.
• To understand the impact of POLQ insufficiency on DNA repair and chromosomal abnormalities.

Main Methods:

• Utilized independent models of POLQ insufficiency in cells undergoing telomere crisis.
• Employed high-throughput sequencing of telomere fusion amplicons.
• Analyzed telomere lengths, fusion frequencies, and chromosomal abnormalities.

Main Results:

• POLQ-deficient cells resisted crisis-induced growth deceleration despite increased telomere fusions.
• POLQ-deficient cells showed longer telomeres, elevated erosion and fusion rates, and reduced chromosomal abnormalities.
• Increased inter-chromosomal telomere fusions and altered repeat array structures (expansions/contractions) were observed in POLQ-deficient cells.

Conclusions:

• POLQ plays a previously unrecognized role in regulating genome-wide repeat arrays.
• POLQ insufficiency can lead to increased genetic heterogeneity and altered genome stability.
• Findings suggest caution regarding POLQ inhibitors in cancer treatment due to potential for driving clonal evolution and drug resistance.