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DsrA regulatory RNA represses both hns and rbs D m RNA s through distinct mechanisms in E scherichia coli
Author(s) -
Lalaouna David,
Morissette Audrey,
Carrier MarieClaude,
Massé Eric
Publication year - 2015
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/mmi.13129
Subject(s) - biology , rna , messenger rna , transfer rna , translation (biology) , rpos , genetics , degradosome , microbiology and biotechnology , gene expression , gene , promoter
Summary The 87 nucleotide long DsrA s RNA has been mostly studied for its translational activation of the transcriptional regulator RpoS . However, it also represses hns m RNA , which encodes H ‐ NS , a major regulator that affects expression of nearly 5% of E scherichia coli genes. A speculative model previously suggested that DsrA would block hns m RNA translation by binding simultaneously to start and stop codon regions of hns m RNA (coaxial model). Here, we show that DsrA efficiently blocked translation of hns m RNA by base‐pairing immediately downstream of the start codon. In addition, DsrA induced hns m RNA degradation by actively recruiting the RNA degradosome complex. Data presented here led to a model of DsrA action on hns m RNA , which supports a canonical mechanism of s RNA ‐induced m RNA degradation by binding to the translation initiation region. Furthermore, using MS 2‐affinity purification coupled with RNA sequencing technology (MAPS), we also demonstrated that DsrA targets rbs D m RNA , involved in ribose utilization. Surprisingly, DsrA base pairs far downstream of rbs D start codon and induces rapid degradation of the transcript. Thus, our study enables us to draw an extended DsrA targetome.