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Control of replication of plasmid R1: the duplex between the antisense RNA, CopA, and its target, CopT, is processed specifically in vivo and in vitro by RNase III.
Author(s) -
Blomberg P.,
Wagner E. G.,
Nordström K.
Publication year - 1990
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1002/j.1460-2075.1990.tb07405.x
Subject(s) - biology , rnase h , rnase p , antisense rna , rna , plasmid , duplex (building) , in vivo , in vitro , microbiology and biotechnology , ribozyme , replication (statistics) , genetics , gene , dna , virology
The replication frequency of IncFII plasmids is regulated through the availability of a rate‐limiting protein, RepA. The synthesis of this protein is controlled post‐transcriptionally by a small antisense RNA, CopA, which binds to the leader region of the RepA mRNA (CopT). In this communication we report studies of the IncFII plasmid R1. We show that the duplex between CopA and CopT is cleaved specifically in vivo. The in vivo cleavage maps to the same position as that resulting from in vitro cleavage of a CopA/CopT duplex by purified RNase III. By introducing plasmids carrying translational repA‐lacZ fusions into cells deficient in RNase III we show that the expression of repA is elevated when RNase III activity is severely decreased. Hence, cleavage by RNase III seems to be a key event in the copy number control system of plasmid R1.