The rate of processing and degradation of antisense RNAI regulates the replication of ColE1-type plasmids in vivo.
We show that the rate of degradation of RNAI, an anti-sense repressor of the replication primer RNAII, is a key element of control in the replication of ColE1-type plasmids in vivo. Cleavage of RNAI by RNAase E, a ribosomal RNA-processing enzyme encoded or controlled by the rne (also known as ams) locus, relieves repression by endonucleolytically converting RNAI to a very rapidly decaying product, pRNAI-5. A 5' triphosphate-terminated homolog of pRNAI-5 is degraded slowly and consequently inhibits replication. Nucleotide substitutions within the RNAase E cleavage sequence alter RNAI half-life and plasmid copy number, changing also the incompatibility phenotype. RNAI variants lacking the sequence cleaved by RNAase E are eliminated by growth rate-dependent degradation, resulting in growth-responsive control of plasmid replication and copy number.
Lin-Chao
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Institute of Molecular Biology, Academia Sinica, Nankang Taipei, Taiwan, Republic of China.
Cohen
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D003086:Bacteriocin Plasmids / Q000235:genetics*; D001483:Base Sequence; D002455:Cell Division; D004261:DNA Replication; D004722:Endoribonucleases / Q000378:metabolism; D004926:Escherichia coli / Q000235:genetics*; D005798:Genes, Bacterial; D006860:Hydrogen Bonding; D008969:Molecular Sequence Data; D015394:Molecular Structure; D010957:Plasmids; D016372:RNA, Antisense / Q000378:metabolism*; D012329:RNA, Bacterial / Q000378:metabolism*
C042027:RNA I; D016372:RNA, Antisense; D012329:RNA, Bacterial; D004722:Endoribonucleases; C022537:ribonuclease E