title: Construction of an Oscillator Gene Circuit by Negative and Positive Feedbacks.
abstract: Synthetic oscillators are gene circuits in which the protein expression will change over time. The delay of transcription, translation, and protein folding is used to form this kind of behavior. Here, we tried to design a synthetic oscillator by a negative feedback combined with a positive feedback. With the mutant promoter PLacC repressed by LacIq and PLux activated by AHL-bound LuxR, two gene circuits, Os-LAA and Os-ASV, were constructed and introduced into LacI-deleted E. coli DH5α cells. When glucose was used as the carbon source, a low level of fluorescence was detected in the culture, and the bacteria with Os-ASV showed no oscillation, whereas a small portion of those carrying Os-LAA demonstrated oscillation behavior with a period of about 68.3 ± 20 min. When glycerol was used as the carbon source, bacteria with Os-ASV demonstrated high fluorescence value and oscillation behavior with the period of about 121 ± 21 min.
authors.affiliation: State Key Laboratory of Bioreactor Engineering, New World Institute of Biotechnology, East China University of Science and Technology, Shanghai 200237, P.R. China.
authors.forename: Shihui
authors.initials: S
authors.lastname: Shen
authors.affiliation: State Key Laboratory of Bioreactor Engineering, New World Institute of Biotechnology, East China University of Science and Technology, Shanghai 200237, P.R. China.
authors.forename: Yushu
authors.initials: Y
authors.lastname: Ma
authors.affiliation: State Key Laboratory of Bioreactor Engineering, New World Institute of Biotechnology, East China University of Science and Technology, Shanghai 200237, P.R. China.
authors.forename: Yuhong
authors.initials: Y
authors.lastname: Ren
authors.affiliation: State Key Laboratory of Bioreactor Engineering, New World Institute of Biotechnology, East China University of Science and Technology, Shanghai 200237, P.R. China.
authors.forename: Dongzhi
authors.initials: D
authors.lastname: Wei
mesh_terms: D004926:Escherichia coli / Q000235:genetics* / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000235:genetics* / Q000378:metabolism; D015964:Gene Expression Regulation, Bacterial; D053263:Gene Regulatory Networks; D011401:Promoter Regions, Genetic
chemical_list: D029968:Escherichia coli Proteins
keywords: lactose operon; oscillator; quorum-sensing system; regulation