Empirical Support for Light Sensors

Light sensor systems have been used for many years and lots of labs and iGEM teams have successfully used these systems. We searched the original investigation from Pub-Med and excitingly, we found three light-sensing systems, which can regulate the expression of down-stream reporter genes in response to the intensity of different light wavelength.

Blue Light System

For the blue light system, the reporter gene is DsRed and the fluorescences/OD600 decreases with the intensity of blue light.[Fig 1]

[Fig 1] DsRed expression from pDusk (●) decreases hyperbolically with increasing intensity between 0 and100 nW cm-2 of 470-nm light; Illumination with white light leads to similar expression levels as under blue light.

Red Light System

For the red light system, the expression of report gene lacZ increases with the intensity of red light when the wavelength is 650nm [Fig2]

[Fig 2]Strain expressing the red sensor only (red circles) was exposed to varying intensities of 650 nm light. the red sensor data (squares) corresponds to the right axis

Green Light System

For the green light system, the expression of report gene increases with the intensity of green light.[Fig3]

[Fig 3] Strain expressing the green sensor only (green circles) was exposed to varying intensities of 532 nm light. the green sensor data (squares) correspond to the left axis

References

OHLENDORF, R., VIDAVSKI, R. R., ELDAR, A., MOFFAT, K. & M GLICH, A. 2012. From dusk till dawn: One-plasmid systems for light-regulated gene expression. Journal of Molecular Biology, 416, 534-542.

TABOR, J. J., LEVSKAYA, A. & VOIGT, C. A. 2011. Multichromatic control of gene expression in escherichia coli. Journal of Molecular Biology, 405, 315-324.