Related Experiment Videos
Nucleotide sequence of the rep gene of staphylococcal plasmid pCW7
1Department of Biochemistry, University of Leicester, United Kingdom.
Abstract:
Previous heteroduplex mapping studies showed that staphylococcal plasmid pCW7 belongs to the pT181 family of small antibiotic resistance plasmids which replicate by a rolling-circle mechanism. Replication in each case is initiated at the plasmid origin (ori) by a plasmid-encoded protein. Rep, which makes a sequence-specific single-stranded nick to form a covalent Rep-ori replication intermediate. A comparison of sequencing results for the repN gene of pCW7 with data for the products of five other homologous rep genes allows a prediction to be made of the segments of the primary structure of Rep which are likely to be responsible for plasmid-specific recognition of the ori region by each Rep protein.
Insights
Staphylococcal plasmid pCW7 replication involves a Rep protein initiating rolling-circle replication. Researchers identified key Rep protein segments responsible for specific origin recognition in antibiotic resistance plasmids.
Area of Science:
- Molecular Biology
- Genetics
- Microbiology
Background:
- Staphylococcal plasmid pCW7 is a small antibiotic resistance plasmid.
- It replicates via a rolling-circle mechanism initiated by a Rep protein.
- The Rep protein makes a sequence-specific nick at the plasmid origin (ori).
Purpose of the Study:
- To predict the structural segments of the Rep protein responsible for specific ori recognition.
- To compare the repN gene of pCW7 with homologous rep genes.
Main Methods:
- Heteroduplex mapping studies.
- Sequencing of the repN gene of pCW7.
- Comparison with sequencing data from five other homologous rep genes.
Main Results:
- Previous studies confirmed pCW7 belongs to the pT181 family.
- Replication initiation involves a Rep protein and a Rep-ori intermediate.
- Specific Rep protein segments likely mediate plasmid-specific ori recognition.
Conclusions:
- The study predicts key structural determinants within Rep proteins for origin binding.
- This provides insight into the specificity of rolling-circle replication in antibiotic resistance plasmids.