Figure 5.

Mechanistic model of Mms1 function at G4 structures. Mms1, perhaps in complex with an interaction partner, binds to G4 structures formed in G1 phase or in early S phase. It binds only to G4 structures form on the lagging strand template for DNA replication. During S phase, the replication fork passes the unsolved G4 structures leaving a gap behind. Mms1 enables (directly or indirectly) the binding of Pif1, which unwinds the G4 structure in late S phase. The resulting gap at the resolved G4 structure is then repaired via a so far unknown mechanism.