The pcnB gene of Escherichia coli, which is required for ColE1 copy number maintenance, is dispensable.

AUTOR(ES)

Masters, M

RESUMO

The pcnB gene product of Escherchia coli is required for copy number maintenance of plasmids related to ColE1 and also for that of the IncFII plasmid R1. Because PcnB is similar to the tRNA-binding protein tRNA nucleotidyltransferase, we have suggested that the protein would be required only for processes in which an RNA is a prominent regulatory component. This appears to be so; strains deleted for pcnB, although defective in ColE1 and R1 plasmid maintenance, maintain the iteron-regulated plasmids F and P1 normally. We also find that strains deleted for pcnB grow normally, demonstrating that PcnB has no essential cellular role under the conditions tested and suggesting that regulation by antisense RNAs similar to RNAI has no critical role in any essential host process. We confirm by immunological tests that PcnB is likely to be the commercially available enzyme poly(A) polymerase.

Documentos Relacionados

• ColE1 copy number mutants.
• Genetics and sequence analysis of the pcnB locus, an Escherichia coli gene involved in plasmid copy number control.
• The Escherichia coli pcnB gene promotes adenylylation of antisense RNAI of ColE1-type plasmids in vivo and degradation of RNAI decay intermediates.
• Suppression of ColE1 high-copy-number mutants by mutations in the polA gene of Escherichia coli.
• The heat-shock DnaK protein is required for plasmid R1 replication and it is dispensable for plasmid ColE1 replication.