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Mechanisms for Hfq-Independent Activation of rpoS by DsrA, a Small RNA, in Escherichia coli.
Mol Cells. 2019 May 31; 42(5):426-439.MC

Abstract

Many small RNAs (sRNAs) regulate gene expression by base pairing to their target messenger RNAs (mRNAs) with the help of Hfq in Escherichia coli. The sRNA DsrA activates translation of the rpoS mRNA in an Hfq-dependent manner, but this activation ability was found to partially bypass Hfq when DsrA is overproduced. The precise mechanism by which DsrA bypasses Hfq is unknown. In this study, we constructed strains lacking all three rpoS-activating sRNAs (i.e., ArcZ, DsrA, and RprA) in hfq+ and Hfq- backgrounds, and then artificially regulated the cellular DsrA concentration in these strains by controlling its ectopic expression. We then examined how the expression level of rpoS was altered by a change in the concentration of DsrA. We found that the translation and stability of the rpoS mRNA are both enhanced by physiological concentrations of DsrA regardless of Hfq, but that depletion of Hfq causes a rapid degradation of DsrA and thereby decreases rpoS mRNA stability. These results suggest that the observed Hfq dependency of DsrA-mediated rpoS activation mainly results from the destabilization of DsrA in the absence of Hfq, and that DsrA itself contributes to the translational activation and stability of the rpoS mRNA in an Hfq-independent manner.

Authors+Show Affiliations

Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea.Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea.Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea.Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea.Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea.Department of Chemistry, Korea Advanced Institute of Science and Technology (KAIST), Daejeon 34141, Korea.

Pub Type(s)

Journal Article

Language

eng

PubMed ID

31085808

Citation

Kim, Wonkyong, et al. "Mechanisms for Hfq-Independent Activation of rpoS By DsrA, a Small RNA, in Escherichia Coli." Molecules and Cells, vol. 42, no. 5, 2019, pp. 426-439.
Kim W, Choi JS, Kim D, et al. Mechanisms for Hfq-Independent Activation of rpoS by DsrA, a Small RNA, in Escherichia coli. Mol Cells. 2019;42(5):426-439.
Kim, W., Choi, J. S., Kim, D., Shin, D., Suk, S., & Lee, Y. (2019). Mechanisms for Hfq-Independent Activation of rpoS by DsrA, a Small RNA, in Escherichia coli. Molecules and Cells, 42(5), 426-439. https://doi.org/10.14348/molcells.2019.0040
Kim W, et al. Mechanisms for Hfq-Independent Activation of rpoS By DsrA, a Small RNA, in Escherichia Coli. Mol Cells. 2019 May 31;42(5):426-439. PubMed PMID: 31085808.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - Mechanisms for Hfq-Independent Activation of rpoS by DsrA, a Small RNA, in Escherichia coli. AU - Kim,Wonkyong, AU - Choi,Jee Soo, AU - Kim,Daun, AU - Shin,Doohang, AU - Suk,Shinae, AU - Lee,Younghoon, PY - 2019/03/08/received PY - 2019/03/11/accepted PY - 2019/5/16/pubmed PY - 2019/11/13/medline PY - 2019/5/16/entrez KW - DsrA KW - Escherichia coli KW - Hfq KW - rpoS KW - small RNAs SP - 426 EP - 439 JF - Molecules and cells JO - Mol Cells VL - 42 IS - 5 N2 - Many small RNAs (sRNAs) regulate gene expression by base pairing to their target messenger RNAs (mRNAs) with the help of Hfq in Escherichia coli. The sRNA DsrA activates translation of the rpoS mRNA in an Hfq-dependent manner, but this activation ability was found to partially bypass Hfq when DsrA is overproduced. The precise mechanism by which DsrA bypasses Hfq is unknown. In this study, we constructed strains lacking all three rpoS-activating sRNAs (i.e., ArcZ, DsrA, and RprA) in hfq+ and Hfq- backgrounds, and then artificially regulated the cellular DsrA concentration in these strains by controlling its ectopic expression. We then examined how the expression level of rpoS was altered by a change in the concentration of DsrA. We found that the translation and stability of the rpoS mRNA are both enhanced by physiological concentrations of DsrA regardless of Hfq, but that depletion of Hfq causes a rapid degradation of DsrA and thereby decreases rpoS mRNA stability. These results suggest that the observed Hfq dependency of DsrA-mediated rpoS activation mainly results from the destabilization of DsrA in the absence of Hfq, and that DsrA itself contributes to the translational activation and stability of the rpoS mRNA in an Hfq-independent manner. SN - 0219-1032 UR - https://www.unboundmedicine.com/medline/citation/31085808/Mechanisms_for_Hfq_Independent_Activation_of_rpoS_by_DsrA_a_Small_RNA_in_Escherichia_coli_ L2 - https://dx.doi.org/10.14348/molcells.2019.0040 DB - PRIME DP - Unbound Medicine ER -