Mechanisms coordinating replication and transcription (236.2)

S-phase transcription jeopardizes the integrity of replicating chromosomes by hampering replication fork progression. DNA topoisomerases, and the Mec1/ATR checkpoint response contribute to coordinate the clash between replication forks and transcribed genes, counteracting the accumulation of reversed forks, R-loops and DNA breaks. Replication termination occurs at specific loci, known as termination zones (TERs). TERs are characterized by the presence of pausing elements, including PolII and PolIII-mediated transcribed units. We studied the events that mediate replication termination at TERs. We found that specialized DNA helicases mediate replicon fusion during termination and counteract the accumulation of RNA-DNA hybrids at TERs. The Mec1 checkpoint also participates in the replication termination events. We will discuss the mechanisms controlling replication termination at TERs.