The underlying premise of this model is tat the cell's highly processive replicase, unable to traverse the blocking lesion, dissociates from the template at the site of the lesion and is replaced by one of the distributive lesion-replicating polymerases described herein. These polymerases add 1 or 2 nucleotides to the nascent DNA chain opposite the lesion and, as a consequence, alleviate the kinetic block to replication. Once this is achieved, the cell's main replicase is able to reassemble on the 3' primer terminus and resumes its job of genome duplication. Depending on the lesion encountered and the fidelity of the DNA polymerase utilized for translesion replication, the bypass reaction will either be error free or error prone.
