Bacteriophage T4 proteins replicate plasmids with a preformed R loop at the T4 ori(uvsY) replication origin in vitro

Mol Cell. 2001 Jan;7(1):31-41. doi: 10.1016/s1097-2765(01)00152-6.


Bacteriophage T4 DNA replication proteins catalyze complete unidirectional replication of plasmids containing the T4 ori(uvsY) replication origin in vitro, beginning with a preformed R loop at the position of the origin R loop previously identified in vivo. T4 DNA polymerase, clamp, clamp loader, and 32 protein are needed for initial elongation of the RNA, which serves as the leading-strand primer. Normal replication is dependent on T4 41 helicase and 61 primase and is strongly stimulated by the 59 helicase loading protein. 59 protein slows replication without the helicase. As expected, leading-strand synthesis stalls prematurely in the absence of T4 DNA topoisomerase. A DNA unwinding element (DUE) is essential for replication, but the ori(uvsY) DUE can be replaced by other DUE sequences.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Bacteriophage T4 / enzymology
  • Bacteriophage T4 / genetics*
  • DNA Helicases / metabolism
  • DNA Ligases / metabolism
  • DNA Replication / physiology*
  • DNA Topoisomerases, Type I / metabolism
  • DNA, Viral / genetics
  • DNA-Directed DNA Polymerase / metabolism
  • In Vitro Techniques
  • Membrane Proteins / genetics
  • Nucleic Acid Conformation
  • Plasmids / chemistry
  • Plasmids / genetics*
  • Replication Origin / genetics*
  • Ribonuclease H / metabolism
  • Viral Proteins / genetics


  • DNA, Viral
  • Membrane Proteins
  • UvsY protein, Enterobacteria phage T4
  • Viral Proteins
  • DNA-Directed DNA Polymerase
  • Ribonuclease H
  • DNA Helicases
  • DNA Topoisomerases, Type I
  • DNA Ligases