Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2016 Jul;26(7):854-7.
doi: 10.1038/cr.2016.74. Epub 2016 Jun 17.

An extraordinary stringent and sensitive light-switchable gene expression system for bacterial cells

Xianjun Chen  1   2   3 , Renmei Liu  1   2 , Zhengcai Ma  1 , Xiaopei Xu  1   2 , Haoqian Zhang  4 , Jianhe Xu  1 , Qi Ouyang  4 , Yi Yang  1   2   3
Affiliations

An extraordinary stringent and sensitive light-switchable gene expression system for bacterial cells

Xianjun Chen et al. Cell Res. 2016 Jul.
No abstract available

PubMed Disclaimer

Figures

Figure 1
Figure 1
The LightOff gene expression system. (A) Schematic representation of the LightOff system. Upon light exposure, the light-switchable repressor LEVI is induced to form homodimers, which then bind to the operator sequence and repress the activity of promoter by blocking the attachment of RNA polymerase to the promoter. Removal of blue light results in gradual dissociation of the dimers and transcription activation. (B) Comparison of gene expression regulation by various chemical- or light-regulated systems. mCherry expression regulated by the LightOff system in JM109 (DE3, ΔsulA, ΔLexA) cells and pDusk system in BL21 (DE3) cells was analyzed 18 h after cells were cultured with light illumination (non-induction) or in darkness (induction). mCherry expression regulated by pET system in BL21 (DE3) pLysS (pET system1) or BL21(DE3) (pET system2) cells and pBAD system in TOP10 cells was analyzed 18 h after cells were cultured without (non-induction) or with addition of chemical inducers (induction). Data shown were normalized to mCherry expression level in BL21(DE3) cells with the pET system in the presence of chemical inducer. (C) Fast repression kinetics of LightOff system in batch culture. JM109 (DE3; ΔsulA ΔLexA) cells transformed with LightOff system were cultured in darkness and then transferred to blue light at the indicated time points (black arrow). Data were normalized to the mCherry expression level in dark conditions. (D) Schematic representation of the Inverted-LightOff system. cI repressor, which can repress the activity of R-O12 promoter, is under the control of the LightOff system. Upon light illumination, LEVI homodimerizes, represses the expression of cI repressor and initiates target gene expression. (E) Quantitative control of gene expression by modulating the light irradiance in the Inverted-LightOff system. Data were normalized to the maximal expression level upon light irradiance. (F) Comparison of the performance of the Inverted-LightOff system with inverted T7 system. Data were normalized to mCherry expression level induced by the inverted T7 system without IPTG. (G) 5-L bioreactor for large-scale production of recombinant protein by the LightOff system. (H) Light sensitivity of the LightOff system with different VVD mutations. Data were normalized to mCherry expression levels in cells kept in darkness. Inset shows the enlarged region of low light intensities. (I) Adaptability of LEVI in controlling transcriptional activities of various promoters. LexA cognate operator sequence was incorporated into various constitutive promoters, bba-J23110, lacUV5, tac and T7 promoters. Detection of the activities of these promoters upon blue light irradiance or in darkness was conducted in BL21 (DE3) cells. a.u., arbitrary units. Data shown in all bar graphs represent mean ± SEM from three independent experiments.
See this image and copyright information in PMC

References

    1. Levskaya A, Chevalier AA, Tabor JJ, et al. Nature 2005; 438:441–442. - PubMed
    1. Ohlendorf R, Vidavski RR, Eldar A, et al. J Mol Biol 2012; 416:534–542. - PubMed
    1. Tabor JJ, Levskaya A, Voigt CA. J Mol Biol 2011; 405:315–324. - PMC - PubMed
    1. Schmidl SR, Sheth RU, Wu A, et al. ACS Synth Biol 2014; 3:820–831. - PubMed
    1. Olson EJ, Hartsough LA, Landry BP, et al. Nat Methods 2014; 11:449–455. - PubMed

Publication types

MeSH terms

LinkOut - more resources