Salicylate Inducible System

Countdown

This page is under Mathieu's responsibility

• Deadline: 08/oct.
  • Final text
• Deadline: 12/oct
  • Final review by Olivier

Ancien abstract

In nature, a lemon is firstly green and becomes yellow after some month. We would like to follow this ripeness transforming our lemon from green to yellow. In order to make our lemon looks green and having reported that there is no green chromoprotein in the RFC, we would like to fuse a yellow chromoprotein with a blue one separated by a linker containing two amber stop codon. Thus, the expression of a tRNA suppressor would suppress amber stop codon and allow the translation of the yellow and blue fusion chromoprotein, hopefully resulting in a green chromoprotein. Then, in the absence of the tRNA suppressor, only the yellow chromoprotein would be translated, allowing our lemon to switch from green to yellow.

The aim of this section is to simulate appearance of a lemon and its ripening process by:

1. Making bacteria display a green color. This part required the design of a green chromoprotein.
2. Making bacteria change its color gradually from green to yellow through time. This part required the design of a color switch system.

Color Switch system design

Color switch mechanism

At the beginning, salicylate concentration is maximal into the agar media so that supD will be expressed and so the green fusion chromoprotein: bacteria will display a green color. However, as bacteria grow into agar, less salicylate will remain available into the media. Thus, the decrease of the nahR-salicylate complex amount within bacteria will lead to supD downregulation through time. In turn, decrease of supD amount will lead to less codon readthrought and so less translation of the green fusion protein and more translation of the yellow chromoprotein. As a result, bacteria will gradually change from green to yellow.