Rolling circle replication

Definition

Rolling circle replication is a process of DNA replication in circular DNA molecules where a nick in one strand allows the 3' end to serve as a primer for synthesis. It produces multiple linear copies of the circular DNA, which can be used for various cellular processes.

5 Must Know Facts For Your Next Test

1. Rolling circle replication is commonly observed in plasmids, viruses, and some bacterial chromosomes.
2. The process begins with an endonuclease creating a single-strand break or 'nick' in the double-stranded circular DNA.
3. The 3' hydroxyl group at the nick serves as a primer for new strand synthesis by DNA polymerase.
4. As new DNA is synthesized, the original strand is progressively displaced and may eventually form a tail or concatemeric structures.
5. Rolling circle replication is an efficient method for producing multiple copies of genetic material quickly.

Review Questions

• What initiates the rolling circle replication process?
• Which types of organisms or genetic elements commonly utilize rolling circle replication?
• Describe the role of the 3' end created by the nick during rolling circle replication.

Related terms

Plasmid: A small, circular piece of DNA found in bacteria that replicates independently from chromosomal DNA.

Concatemer: A long continuous DNA molecule that contains multiple copies of the same sequence linked in series.

Endonuclease: An enzyme that cleaves the phosphodiester bond within a polynucleotide chain.