DsrA RNA

DsrA RNA is a non-coding RNA that regulates both transcription, by overcoming transcriptional silencing by the nucleoid-associated H-NS protein, and translation, by promoting efficient translation of the stress sigma factor, RpoS. These two activities of DsrA can be separated by mutation: the first of three stem-loops of the 85 nucleotide RNA is necessary for RpoS translation but not for anti-H-NS action, while the second stem-loop is essential for antisilencing and less critical for RpoS translation. The third stem-loop, which behaves as a transcription terminator, can be substituted by the trp transcription terminator without loss of either DsrA function. The sequence of the first stem-loop of DsrA is complementary with the upstream leader portion of RpoS messenger RNA, suggesting that pairing of DsrA with the RpoS message might be important for translational regulation.

There is evidence that DsrA RNA can self-assemble into nanostructures through antisense interactions of three self-complementary regions.