Youve just has a terrific business idea a lavalamp of sorts

You\'ve just has a terrific business idea: a \"lava-lamp\" of sorts that is made of bacteria that fluoresce in the dark through expression of Green Flourescent Protein (GFP). One investor is willing to fund your product if users could make your \"bio-lamp\" blink by pressing a button. Now your job is to propose your idea in writing, so the biotech consulting firm hired by the investor can take a look at your plan. You figured out that what you need to do to make it \'blink\', is express GFP in an oscillatory manner and that you can do this by introducing a modified Lac operon, that instead of lacZ, lacY, and lacA, expresses GFP and any other genes that you want to express. Hint: You can easily make an oscillatory when a gene inhibits itself. Come up with a genetic system that can support oscillatory expression of GFP whenever we want. In other words, a genetic system that can express GFP in an oscillatory manner whenever we add or remove something to/from the culture. You may explain your system in simple terms that describe the components of your genetic system. E.g.: \"We could combine a core promoter to a GFP coding sequence, on the one hand, and an inducible operon that expresses... on the other\". Just make sure to describe the regulatory logic of your system. And yes, you may use any of the elements from the operons. (This can be answered in a simple paragraph stating what you will use and basically decribe how it will be done).

Solution

GFP will be more stable, it will not be optimal for monitoring dynamic changes in gene expression. Fast-degrading fluorescent proteins help to rapidly extinguish the fluorescent signal when the promoter becomes inactive but when this promoter is active, fluorescent protein levels increases to produce a fluorescent signal sufficiently higher than background fluorescence. Thus, an ideal system for monitoring gene expression changes with fast dynamics, utilizes a rapidly degrading fluorescent reporter in conjunction with a promoter that yields maximal reporter protein levels when active.

Ex: Three repressors used to build a synthetic oscillatory network called ‘the repressilator\', and are characterized by the oscillations by quantifying expression levels of a GFP reporter protein in individual E. coli cells. Individual repressilator-containing cells are not synchronized. Thus, observing oscillations in gene expression required tracking expression levels from single cells at multiple time points. This was accomplished by using fluorescence microscopy to monitor temporal oscillations in GFP expression in individual cells.

or simply

combining the core promoter sequence with GFP coding sequence and expressing full-length GFP-tagged proteins for the location of chromosomes at natural levels.