The Mre11-Rad50-Xrs2 (MRX) complex helps drive triplet repeat expansions in yeast.
MRX works independently of homologous recombination to fuel expansions.
Mre11 nuclease activity is dispensable.
MRX likely creates an altered TNR substrate for post replication repair action.
Rad50 is acetylated; Sin3-mediated deacetylation is important for expansions.