title: Two tandem RNase III cleavage sites determine betT mRNA stability in response to osmotic stress in Escherichia coli.
abstract: While identifying genes regulated by ribonuclease III (RNase III) in Escherichia coli, we observed that steady-state levels of betT mRNA, which encodes a transporter mediating the influx of choline, are dependent on cellular concentrations of RNase III. In the present study, we also observed that steady-state levels of betT mRNA are dependent on RNase III activity upon exposure to osmotic stress, indicating the presence of cis-acting elements controlled by RNase III in betT mRNA. Primer extension analyses of betT mRNA revealed two tandem RNase III cleavage sites in its stem-loop region, which were biochemically confirmed via in vitro cleavage assays. Analyses of cleavage sites suggested the stochastic selection of cleavage sites by RNase III, and mutational analyses indicated that RNase III cleavage at either site individually is insufficient for efficient betT mRNA degradation. In addition, both the half-life and abundance of betT mRNA were significantly increased in association with decreased RNase III activity under hyper-osmotic stress conditions. Our findings demonstrate that betT mRNA stability is controlled by RNase III at the post-transcriptional level under conditions of osmotic stress.
authors: Department of Life Science, Chung-Ang University, Seoul, Republic of Korea.
authors: Minji
authors: M
authors: Sim
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.
authors: Se-Hoon
authors: SH
authors: Sim
authors: Department of Life Science, Chung-Ang University, Seoul, Republic of Korea.
authors: Daeyoung
authors: D
authors: Kim
authors: Department of Chemistry, KAIST, Daejeon, Republic of Korea.
authors: Euihan
authors: E
authors: Jung
authors: Department of Chemistry, KAIST, Daejeon, Republic of Korea.
authors: Younghoon
authors: Y
authors: Lee
authors: Department of Life Science, Chung-Ang University, Seoul, Republic of Korea.
authors: Kangseok
authors: K
authors: Lee
mesh_terms: D015152:Blotting, Northern; D002478:Cells, Cultured; D002794:Choline / Q000378:metabolism*; D004926:Escherichia coli / Q000235:genetics / Q000254:growth & development / Q000378:metabolism*; D029968:Escherichia coli Proteins / Q000235:genetics / Q000378:metabolism*; D006207:Half-Life; D026901:Membrane Transport Proteins / Q000235:genetics* / Q000378:metabolism; D009997:Osmotic Pressure; D020871:RNA Stability / Q000235:genetics*; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D043244:Ribonuclease III / Q000378:metabolism*
chemical_list: D029968:Escherichia coli Proteins; D026901:Membrane Transport Proteins; D012333:RNA, Messenger; C065637:choline transporter; D043244:Ribonuclease III; D002794:Choline