DNA repair enzymes favor specific sequences, shaping human genome mutation patterns
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DNA repair enzymes’ sequence preferences influence where mutations accumulate in the human genome, a Weizmann Institute study finds. Published in Nature Communications, the research shows that even genetic letters five positions away from a damage site affect enzyme binding, explaining regional mutation rate differences.
Enzyme Sequence Preferences
Weizmann Institute researchers led by Dr. Ariel Afek developed a chip with thousands of short DNA molecules, each carrying identical damage but varying surrounding sequences. They tested three key DNA repair enzymes and found each enzyme sensitive to the exact combination of genetic bases near the error site. Even bases positioned five steps upstream or downstream influenced recognition and binding. The enzymes’ selectivity suggests that repair is not random but guided by local sequence context.
Structural Features Behind Recognition
The team discovered that preferred sequences share common structural traits. One enzyme favored configurations creating an exceptionally narrow region in the DNA helix. Computer simulations in collaboration with Prof. Brian P. Weiser at Rowan University helped clarify how structural features influence enzyme binding. The findings provide a physical basis for why certain genomic regions are more efficiently repaired than others.
Impact on Mutation Landscape
The balance between DNA damage and repair determines mutation accumulation rates across the genome. The study shows that repair enzymes’ sequence preferences act as a filter, leaving distinct mutational ‘scars’ where repair is less effective. These preferences may have shaped the human genome over evolutionary time and could explain why cancer-driving mutations arise in specific genomic hotspots. The research bridges a gap between molecular repair mechanisms and observed mutation patterns.
What's Next
The Weizmann team is now exploring how these repair biases influence cancer cell mutation rates. It remains unclear whether manipulating repair enzyme activity could prevent harmful mutations or if the inherent sequence preferences are immutable.
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DNA repair enzymes favor specific sequences, shaping human genome mutation patterns
