Contrasting lifestyles of rolling-circle phages and plasmids

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R P Novick1

  • 1Skirball Institute, New York University Medical School, NY 10016, USA.

Trends in Biochemical Sciences
|December 16, 1998
PubMed

Insights

Prokaryotic phages and plasmids use rolling-circle DNA replication differently. Phi X174 phage prioritizes progeny production, while pT181 plasmid ensures precise replication control.

Area of Science:

  • Molecular Biology
  • Genetics
  • Microbiology

Background:

  • Rolling-circle replication is a mechanism used by small prokaryotic genomes like phages and plasmids.
  • These replicons have evolved distinct strategies for utilizing this replication method.

Purpose of the Study:

  • To compare and contrast the rolling-circle replication strategies of the phi X174 phage and the pT181 plasmid.
  • To highlight how these strategies are adapted to their specific biological requirements.

Main Methods:

  • Comparative analysis of rolling-circle replication mechanisms.
  • Examination of initiator protein function (monomeric vs. dimeric).
  • Analysis of termination processes and protein recycling/inactivation.

Main Results:

  • Phi X174 phage employs a monomeric initiator protein catalytically for high-volume progeny production, featuring incomplete termination and initiator recycling.
  • The pT181 plasmid utilizes a dimeric initiator protein stoichiometrically for precise replication control, with complete termination and initiator inactivation.

Conclusions:

  • The phi X174 phage and pT181 plasmid exemplify divergent adaptations of rolling-circle replication.
  • These distinct models offer insights into the diverse evolutionary strategies of prokaryotic replicons.

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