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Transcriptional regulation of F plasmid gene srnB : rifampicin‐promoted in vitro readthrough of a terminator in the leader region
Author(s) -
Akimoto S.,
Sakikawa T.,
Ono K.,
Ono T.,
Ohnishi Y.
Publication year - 1989
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.1365-2958.1989.tb00227.x
Subject(s) - terminator (solar) , biology , gene , transcription (linguistics) , plasmid , rifampicin , gene expression , microbiology and biotechnology , rna polymerase , rna , nuclease , messenger rna , genetics , ionosphere , linguistics , philosophy , physics , astronomy , antibiotics
Summary srnB is an F‐plasmid encoded gene, otherwise silent, whose expression is induced by added rifampicin, leading to the release of cellular Mg 2+ and degradation of stable RNA. In the absence of rifampicin, transcripts from the srnB gene were relatively short. S1 nuclease mapping revealed that the short mRNA species terminated within the leader, at the 3’end of a potential stem‐and‐loop structure. A deletion in the stem‐loop resulted in constitutive synthesis of the mRNA that extended beyond the termination site into the structural gene. Even with the wild‐type gene, transcription continued beyond the terminator sequence in the presence of added rifampicin. Most of the transcripts synthesized in the presence of rifampicin were long enough to encode the srnB protein. We hypothesize from these results that RNA polymerase associated with rifampicin can read through the terminator to induce srnB expression.