Journal Article

Rolling-Circle Plasmid pKYM Re-initiates DNA Replication

Hiroo Yasukawa and Yukito Masamune

in DNA Research

Published on behalf of Kazusa DNA Research Institute

Volume 4, issue 3, pages 193-197
Published in print January 1997 | ISSN: 1340-2838
Published online January 1997 | e-ISSN: 1756-1663 | DOI: http://dx.doi.org/10.1093/dnares/4.3.193

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It is believed that rolling-circle plasmids are incapable of re-initiation since they have to maintain their copy number and this is one of the difierences between plasmids and phages as phi-x174. To examine whether a rolling-circle plasmid pKYM is incapable of re-initiating DNA replication, we constructed a plasmid that carries both the pKYM origin (fragment 13, 173 bp) and its truncated origin (fragment 32, 56 bp) in the same orientation. This plasmid yielded two smaller plasmids in the presence of RepK, an initiator protein. We showed that RepK can bind to the fragment 13 but not to fragment 32 which lacks the 3′-moiety of fragment 13. These results imply that RepK initiates DNA replication from fragment 13 and terminates at fragment 32, then the same RepK is used for re-initiation of replication from the fragment 32 region. pKYM is likely to be a unique plasmid that re-initiates DNA replication like a phage phi-x174.

Keywords: rolling-circle; pKYM; re-initiation

Journal Article.  0 words. 

Subjects: Genetics and Genomics

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