Genome Instability Induced by Topoisomerase Misfunction.

Area of Science:

• Molecular Biology
• Genetics
• Biochemistry

Background:

• Topoisomerases regulate DNA topology through transient DNA strand breaks (DSBs).
• Their mechanism involves a reversible protein/DNA complex, enabling rapid resealing to prevent persistent DNA damage.
• Impaired resealing by small molecules, DNA structures, or mutations can lead to genome instability.

Purpose of the Study:

• To review recent studies on topoisomerase function and dysfunction.
• To highlight the role of topoisomerases in genome instability and cancer.
• To explore cellular mechanisms that limit topoisomerase-induced genetic damage.

Main Methods:

• Literature review of recent studies on topoisomerases.
• Analysis of enzyme/DNA adduct consequences for Type I and Type II topoisomerases.
• Examination of genetic alterations caused by topoisomerase mis-function.

Main Results:

• Topoisomerase I (Top1) action on ribonucleotides causes deletions; mutant Top1 generates large deletions.
• Topoisomerase II (Top2) targeting by small molecules or mutations leads to duplications.
• Both Top1 and Top2 can induce large genomic rearrangements and translocations.

Conclusions:

• Topoisomerase mis-function is a pathogenic mechanism contributing to oncogenic progression.
• Understanding how cells limit topoisomerase-induced genome instability is critical for cancer research.
• Topoisomerases play significant roles in genetic alterations observed in cancer cells.