In vivo studies suggest that replication forks are arrested by encounters with 
head-on transcription complexes. Yet, the fate of the replisome and RNA 
polymerase (RNAP) after a head-on collision is unknown. We found that the 
Escherichia coli replisome stalls upon collision with a head-on transcription 
complex, but instead of collapsing, the replication fork remains highly stable 
and eventually resumes elongation after displacing the RNAP from DNA. We also 
found that the transcription-repair coupling factor Mfd promotes direct restart 
of the fork after the collision by facilitating displacement of the RNAP. These 
findings demonstrate the intrinsic stability of the replication apparatus and a 
previously unknown role for the transcription-coupled repair pathway in 
promoting replication past a RNAP block.