Rep provides a second motor at the replisome to promote duplication of protein-bound DNA.
Nucleoprotein complexes present challenges to genome stability by acting as potent blocks to replication. One attractive model of how such conflicts are resolved is direct targeting of blocked forks by helicases with the ability to displace the blocking protein-DNA complex. We show that Rep and UvrD each promote movement of E. coli replisomes blocked by nucleoprotein complexes in vitro, that such an activity is required to clear protein blocks (primarily transcription complexes) in vivo, and that a polarity of translocation opposite that of the replicative helicase is critical for this activity. However, these two helicases are not equivalent. Rep but not UvrD interacts physically and functionally with the replicative helicase. In contrast, UvrD likely provides a general means of protein-DNA complex turnover during replication, repair, and recombination. Rep and UvrD therefore provide two contrasting solutions as to how organisms may promote replication of protein-bound DNA.
Guy
Colin P
CP
Institute of Medical Sciences, University of Aberdeen, Foresterhill, UK.
Atkinson
John
J
Gupta
Milind K
MK
Mahdi
Akeel A
AA
Gwynn
Emma J
EJ
Rudolph
Christian J
CJ
Moon
Peter B
PB
van Knippenberg
Ingeborg C
IC
Cadman
Chris J
CJ
Dillingham
Mark S
MS
Lloyd
Robert G
RG
McGlynn
Peter
P
D003470:Culture Media; D004265:DNA Helicases / Q000378:metabolism*; D004261:DNA Replication; D004269:DNA, Bacterial / Q000378:metabolism*; D004259:DNA-Directed DNA Polymerase / Q000378:metabolism*; D053488:DnaB Helicases / Q000378:metabolism; D004926:Escherichia coli / Q000166:cytology / Q000201:enzymology / Q000254:growth & development; D029968:Escherichia coli Proteins / Q000378:metabolism*; D005816:Genetic Complementation Test; D020409:Molecular Motor Proteins / Q000378:metabolism*; D009097:Multienzyme Complexes / Q000378:metabolism*; D009154:Mutation / Q000235:genetics; D009698:Nucleoproteins / Q000378:metabolism; D011485:Protein Binding; D013489:Suppression, Genetic; D014158:Transcription, Genetic; D000099272:Replisomes
D003470:Culture Media; D004265:DNA Helicases; D004269:DNA, Bacterial; D004259:DNA-Directed DNA Polymerase; D053488:DnaB Helicases; D029968:Escherichia coli Proteins; D020409:Molecular Motor Proteins; D009097:Multienzyme Complexes; D009698:Nucleoproteins; D000099272:Replisomes; C506744:rep protein, E coli; C506746:UvrD protein, E coli; C506730:dnaB protein, E coli