The yeast and human FACT complexes resolve R-loop-mediated transcription-replication conflicts

Transcription is a major obstacle for replication fork progression and transcription-replication collisions constitute a main cause of genome instability. At a genome-wide scale these obstacles can be detected by the accumulation of the replicative Rrm3 helicase required for RF progression through protein obstacles. Here we show that FACT, a chromatin-reorganizing complex that swaps nucleosomes around the RNA polymerase during transcription elongation and that also has a role in replication, is needed to resolve transcription-replication conflicts in Saccharomyces cerevisiae. Importantly, ChIP-chip analyses of Rrm3 reveal that replication progression impairment in FACT mutants occur genome-wide, but preferentially at highly transcribed regions. ChIP-chip studies were perfomed with antibodies against Rrm3-FLAG in the yeast S. cerevisiae.