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MutLα suppresses error-prone DNA mismatch repair and preferentially protects noncoding DNA from mutations
Lyudmila Y Kadyrova1, Piotr A Mieczkowski2, Farid A Kadyrov1
1Division of Biochemistry and Molecular Biology, Department of Biomedical Sciences, Southern Illinois University School of Medicine, Carbondale, IL 62901, USA.
Biorxiv : the Preprint Server for Biology
|April 15, 2024
Summary
The DNA mismatch repair (MMR) system, particularly MutLα, is crucial for genome stability. Its absence causes a significant increase in mutations, highlighting its role in preventing cancer.
Area of Science:
- Genetics
- Molecular Biology
- Cancer Research
Background:
- The DNA mismatch repair (MMR) system is essential for maintaining genome stability by correcting DNA polymerase errors.
- MutLα is a key eukaryotic MMR factor involved in genome integrity and cancer prevention.
Approach:
- Investigated the role of MutLα in genome stability using yeast models.
- Analyzed human whole genome sequencing data from induced pluripotent stem cells.
Key Points:
- Loss of MutLα in yeast increased the mutation rate by ~130-fold, generating small indels and base substitutions.
- MutLα deficiency leads to error-prone MMR, causing specific T>C mutations in 5'-ATA-3' sequences in yeast and 5'-NTN-3' sequences in human cells.
- MutLα-independent MMR suppresses base substitutions in N3 homopolymeric runs and preferentially protects noncoding DNA.
Conclusions:
- MutLα plays a critical role in suppressing genome-wide mutations, particularly base substitutions.
- Both MutLα-dependent and independent MMR mechanisms contribute to genome stability.
- Understanding these MMR pathways is vital for cancer research and therapeutic strategies.
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