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Structural and functional analyses of the FinP antisense RNA regulatory system of the F conjugative piasmid
Author(s) -
Biesen Tim,
Soderbom Fredrik,
Wagner E. Gerhart H.,
Frost Laura S.
Publication year - 1993
Publication title -
molecular microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.857
H-Index - 247
eISSN - 1365-2958
pISSN - 0950-382X
DOI - 10.1111/j.1365-2958.1993.tb00901.x
Subject(s) - biology , rna , antisense rna , primer extension , operon , messenger rna , rnase p , bacterial conjugation , transcription (linguistics) , microbiology and biotechnology , rnase h , plasmid , genetics , dna , gene , escherichia coli , philosophy , linguistics
Summary The efficiency of conjugation of F‐like plasmids is regulated by the FinOP f ertility in hibition system. The transfer ( tra ) operon is under the direct control of the TraJ transcriptional activator which, in turn, is negatively regulated by FinP, an antisense RNA, and FinO, a 22 kDa protein. Recently, FinO has been shown to extend the chemical stability of FinP in vivo in the absence of traJ mRNA. The in vitro secondary structures of both the FinP and TraJ RNAs were determined by the use of single‐ and double‐strand‐specific nucleases; both RNAs were found to have double stem‐loop structures that are complementary to each other and, therefore, FinP RNA and TraJ RNA have the potential to form a duplex with each other. This was verified by in vitro binding experiments. The reaction was shown to be bimolecular with an apparent rate constant ( K app ) of 5 × 10 5 M −1 s −1 , a value that is similar to those found for other natural antisense RNA systems. Preliminary evidence for the in vivo formation of the FinP–TraJ RNA duplex was obtained by primer extension of the traJ mRNA; the presence of both FinO and FinP was required to cause a dramatic reduction in the steady‐state level of traJ mRNA, perhaps as a result of RNase III degradation of the resulting RNA duplex.