Regulation of ompA mRNA stability: the role of a small regulatory RNA in growth phase-dependent control.
The Escherichia coli ompA mRNA, encoding a highly abundant outer membrane protein, has served as a model for regulated mRNA decay in bacteria. The half-life of this transcript correlates inversely with the bacterial growth rate and is growth stage-dependent. The stability of the messenger is determined by the 5'-untranslated region which possesses cleavage sites for RNase E. Hfq binds to this region, is essential for controlling the stability and has been suggested to directly regulate ompA mRNA decay. Here we report that the 78 nucleotide SraD RNA, which is highly conserved among Enterobacteriaceae, acts in destabilizing the ompA transcript when rapidly grown cells enter the stationary phase of growth. During this growth-stage the expression of SraD RNA becomes strongly increased. The SraD-mediated decay of ompA mRNA depends on Hfq and in vitro studies revealed that Hfq facilitates binding of the regulatory RNA to the translational initiation region of the messenger. Deletion of sraD, however, does not significantly affect the stability of the ompA mRNA in slowly growing cells. Our results indicate that distinct regulatory circuits are responsible for growth phase- and growth rate-dependent control of the ompA mRNA stability.
Rasmussen
Anders Aamann
AA
Department of Biochemistry and Molecular Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
Eriksen
Maiken
M
Gilany
Kambiz
K
Udesen
Christina
C
Franch
Thomas
T
Petersen
Carsten
C
Valentin-Hansen
Poul
P
D020121:5' Untranslated Regions / Q000737:chemistry / Q000235:genetics; D001425:Bacterial Outer Membrane Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D048168:Escherichia coli K12 / Q000235:genetics / Q000254:growth & development* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D006207:Half-Life; D035001:Host Factor 1 Protein / Q000235:genetics / Q000378:metabolism; D008969:Molecular Sequence Data; D020871:RNA Stability; D012329:RNA, Bacterial / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D012333:RNA, Messenger / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D022661:RNA, Untranslated / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*
D020121:5' Untranslated Regions; D001425:Bacterial Outer Membrane Proteins; D029968:Escherichia coli Proteins; C087373:Hfq protein, E coli; D035001:Host Factor 1 Protein; D012329:RNA, Bacterial; D012333:RNA, Messenger; D022661:RNA, Untranslated; C078167:OMPA outer membrane proteins