title: Stability of the osmoregulated promoter-derived proP mRNA is posttranscriptionally regulated by RNase III in Escherichia coli.
abstract: The enzymatic activity of Escherichia coli endo-RNase III determines the stability of a subgroup of mRNA species, including bdm, betT, and proU, whose protein products are associated with the cellular response to osmotic stress. Here, we report that the stability of proP mRNA, which encodes a transporter of osmoprotectants, is controlled by RNase III in response to osmotic stress. We observed that steady-state levels of proP mRNA and ProP protein are inversely correlated with cellular RNase III activity and, in turn, affect the proline uptake capacity of the cell. In vitro and in vivo analyses of proP mRNA revealed RNase III cleavage sites in a stem-loop within the 5' untranslated region present only in proP mRNA species synthesized from the osmoregulated P1 promoter. Introduction of nucleotide substitutions in the cleavage site identified inhibited the ribonucleolytic activity of RNase III on proP mRNA, increasing the steady-state levels and half-life of the mRNA. In addition, decreased RNase III activity coincided with a significant increase in both the half-life and abundance of proP mRNA under hyperosmotic stress conditions. Analysis of the RNA bound to RNase III via in vivo cross-linking and immunoprecipitation indicated that this phenomenon is related to the decreased RNA binding capacity of RNase III. Our findings suggest the existence of an RNase III-mediated osmoregulatory network that rapidly balances the expression levels of factors associated with the cellular response to osmotic stress in E. coli.
  
  
  OBJECTIVE
  Our results demonstrate that RNase III activity on proP mRNA degradation is downregulated in Escherichia coli cells under osmotic stress. In addition, we show that the downregulation of RNase III activity is associated with decreased RNA binding capacity of RNase III under hyperosmotic conditions. In particular, our findings demonstrate a link between osmotic stress and RNase III activity, underscoring the growing importance of posttranscriptional regulation in modulating rapid physiological adjustment to environmental changes.
authors: Department of Life Science, Chung-Ang University, Seoul, Republic of Korea.
authors: Boram
authors: B
authors: Lim
authors: Department of Life Science, Chung-Ang University, Seoul, Republic of Korea kangseok@cau.ac.kr.
authors: Kangseok
authors: K
authors: Lee
mesh_terms: D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D015964:Gene Expression Regulation, Bacterial / Q000502:physiology*; D015971:Gene Expression Regulation, Enzymologic / Q000502:physiology; D005838:Genotype; D064587:Osmoregulation / Q000502:physiology*; D012323:RNA Processing, Post-Transcriptional / Q000502:physiology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism*; D043244:Ribonuclease III / Q000235:genetics / Q000378:metabolism; D027981:Symporters / Q000235:genetics / Q000378:metabolism*
chemical_list: D029968:Escherichia coli Proteins; C079244:ProP protein, E coli; D012333:RNA, Messenger; D027981:Symporters; D043244:Ribonuclease III
references: Science. 1997 Sep 5;277(5331):1453-62
references: 9278503
references: Biochemistry. 1996 Jul 9;35(27):8805-14
references: 8688416
references: Microbiol Mol Biol Rev. 1999 Mar;63(1):230-62
references: 10066837
references: Biosci Biotechnol Biochem. 2005 Apr;69(4):740-6
references: 15849412
references: J Mol Microbiol Biotechnol. 2004;8(4):195-200
references: 16179796
references: EMBO J. 2006 Apr 5;25(7):1515-21
references: 16541105
references: Sci STKE. 2006 Oct 17;2006(357):pe43
references: 17047223
references: Mol Microbiol. 2007 Feb;63(3):780-96
references: 17302803
references: FEMS Microbiol Lett. 2008 Aug;285(1):10-5
references: 18510556
references: Methods Enzymol. 2008;447:215-41
references: 19161846
references: Mol Microbiol. 2010 Jan;75(2):413-25
references: 19943899
references: Biochemistry. 2010 Oct 19;49(41):8847-56
references: 20828170
references: FEMS Microbiol Lett. 2011 Feb;315(1):30-7
references: 21133991
references: Biochemistry. 2011 Apr 19;50(15):3095-106
references: 21381725
references: Nucleic Acids Res. 2011 Apr;39(8):3188-203
references: 21149258
references: J Bacteriol. 2012 May;194(9):2214-20
references: 22343302
references: RNA Biol. 2012 Jan;9(1):98-109
references: 22258144
references: J Bacteriol. 2012 Nov;194(22):6046-55
references: 22942248
references: PLoS One. 2013;8(10):e79656
references: 24205389
references: Annu Rev Genet. 2013;47:405-31
references: 24274754
references: Wiley Interdiscip Rev RNA. 2014 Jan-Feb;5(1):31-48
references: 24124076
references: Curr Microbiol. 2014 Apr;68(4):518-23
references: 24343175
references: J Bacteriol. 2014 Mar;196(6):1286-96
references: 24443528
references: Nucleic Acids Res. 2014 Apr;42(7):4669-81
references: 24489121
references: PLoS One. 2014;9(6):e100520
references: 24956275
references: Genes Dev. 1999 Dec 1;13(23):3081-91
references: 10601034
references: Proc Natl Acad Sci U S A. 2000 Jun 6;97(12):6640-5
references: 10829079
references: Biochemistry. 2001 Jun 19;40(24):7324-33
references: 11401581
references: Methods Enzymol. 2001;342:143-58
references: 11586889
references: FEMS Microbiol Rev. 2002 Mar;26(1):49-71
references: 12007642
references: Methods. 2002 Feb;26(2):182-90
references: 12054895
references: Nucleic Acids Res. 2003 Jul 1;31(13):3406-15
references: 12824337
references: Cell. 1980 Jun;20(2):529-42
references: 6248248
references: J Bacteriol. 1981 Jun;146(3):895-901
references: 7016835
references: J Biol Chem. 1983 May 10;258(9):5340-3
references: 6406499
references: J Mol Biol. 1986 Jan 5;187(1):23-32
references: 3007765
references: Mol Gen Genet. 1987 Aug;209(1):28-32
references: 2823071
references: Microbiol Rev. 1989 Mar;53(1):121-47
references: 2651863
references: J Mol Biol. 1993 Jan 5;229(1):268-76
references: 8421314
references: J Bacteriol. 1995 Jan;177(1):144-51
references: 8002611
references: J Bacteriol. 1995 Sep;177(18):5222-31
references: 7545153
references: Mol Microbiol. 1997 Dec;26(5):1125-35
references: 9426147