Involvement of antisense RNA in replication control of the lactococcal plasmid pND324.
pND324 belongs to a family of closely related theta-type plasmids from Lactococcus lactis. An antisense RNA, termed countertranscript (ctRNA), was identified which is complementary to the leader sequence of the mRNA that encodes RepB, a protein essential for plasmid replication. When the synthesis of ctRNA was abolished by site-directed mutagenesis within its promoter region, the mutant replicon showed a 1.8-fold increase in copy number. Similar ctRNA promoter sequences are readily identifiable in 12 other published lactococcal theta-type plasmids, suggesting that they all encode a similar ctRNA-mediated regulatory mechanism.
Department of Biotechnology, University of New South Wales, Sydney, Australia.
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Dunn
D001483:Base Sequence; D004261:DNA Replication; D018628:Gene Dosage; D013294:Lactococcus lactis / Q000235:genetics*; D008957:Models, Genetic; D008969:Molecular Sequence Data; D016297:Mutagenesis, Site-Directed; D009690:Nucleic Acid Conformation; D010957:Plasmids / Q000235:genetics*; D016372:RNA, Antisense / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D012093:Replicon; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA
D016372:RNA, Antisense