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A possible role for the pcnB gene product of Escherichia coli in modulating RNA:RNA interactions


The sequence of the PcnB protein of Escherichia coli, a protein required for copy number maintenance of ColE1-related plasmids, was compared with the PIR sequence database. Strong local similarities to the sequence of the E. coli protein tRNA nucleotidyltransferase were found. Since a substrate of the latter protein, tRNA, structurally resembles the RNAs that control ColE1 copy number we believe that we may have identified a region in PcnB that interacts with these RNAs. Consistent with this idea is our observation that PcnB is required for the replication of R1, a plasmid whose replication is also regulated by a small RNA.

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Correspondence to Millicent Masters.

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Communicated by D.J. Finnegan

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Masters, M., March, J.B., Oliver, I.R. et al. A possible role for the pcnB gene product of Escherichia coli in modulating RNA:RNA interactions. Molec. Gen. Genet. 220, 341–344 (1990).

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Key words

  • Plasmid copy number
  • tRNA nucleotidyltransferase
  • PcnB
  • Replication control
  • ColE1