The proteins that copy DNA are not perfect. Luckily, our cells can fix broken DNA via a process called homologous recombination repair, which involves proteins like RAD51. RAD51 helps protect DNA from being degraded by cell enzymes as it is copied.
David Cortez, PhD, and colleagues reported last month in the journal Cell Reports that another protein they identified, RADX, is a modulator of RAD51. They found that RADX helps keep RAD51 in check in order to make sure exactly the correct amount of DNA repair occurs.
They showed that in cells with mutations in DNA repair genes and RAD51 (often present in cancer), RADX helps protect DNA as it is being copied. However, if RADX is overexpressed, it can prevent RAD51 from binding DNA and thus inhibits DNA replication.
Their work helps us better understand the biology of DNA repair, which is important for understanding why some cancers are more or less resistant to certain therapies.
The research was supported in part by National Institutes of Health grants GM116616 and CA212345.