Biomaterial Database

Contrasting lifestyles of rolling-circle phages and plasmids. 1998

R P Novick

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

The rolling-circle mechanism of DNA replication is used by small prokaryotic genomes, such as single-stranded phages and plasmids. However, phages and plasmids have adapted the rolling-circle mechanism differently to suit their contrasting biological needs. The phi X174 phage uses a monomeric initiator protein catalytically, displays incomplete termination and recycles the initiator protein, in order to mass-produce phage progeny. By contrast, to control replication precisely, the pT181 plasmid uses a dimeric initiator protein stochiometrically, completes termination and inactivates the initiator after each replication cycle. The phi X174 phage and the pT181 plasmid represent paradigmatic adaptations of the rolling-circle mechanism and could provide models for other replicons.

UI	MeSH Term	Description	Entries
D008957	Models, Genetic	Theoretical representations that simulate the behavior or activity of genetic processes or phenomena. They include the use of mathematical equations, computers, and other electronic equipment.	Genetic Models,Genetic Model,Model, Genetic
D010584	Bacteriophage phi X 174	The type species of the genus MICROVIRUS. A prototype of the small virulent DNA coliphages, it is composed of a single strand of supercoiled circular DNA, which on infection, is converted to a double-stranded replicative form by a host enzyme.	Coliphage phi X 174,Enterobacteria phage phi X 174,Phage phi X 174,phi X 174 Phage,Phage phi X174
D010957	Plasmids	Extrachromosomal, usually CIRCULAR DNA molecules that are self-replicating and transferable from one organism to another. They are found in a variety of bacterial, archaeal, fungal, algal, and plant species. They are used in GENETIC ENGINEERING as CLONING VECTORS.	Episomes,Episome,Plasmid
D002384	Catalysis	The facilitation of a chemical reaction by material (catalyst) that is not consumed by the reaction.	Catalyses
D004261	DNA Replication	The process by which a DNA molecule is duplicated.	Autonomous Replication,Replication, Autonomous,Autonomous Replications,DNA Replications,Replication, DNA,Replications, Autonomous,Replications, DNA
D001435	Bacteriophages	Viruses whose hosts are bacterial cells.	Phages,Bacteriophage,Phage
D019281	Dimerization	The process by which two molecules of the same chemical composition form a condensation product or polymer.	Dimerizations