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

Oscillatory GFP expression can be accomplished by cloning the GFP in the mpdified Lac operon,

A lac operon has the basic components as

Catabolite activator Protein (CAP) site : which helps in the proper binding of RNA polymerase to the DNA binding site

Promoter: Region to which the RNA polymerase binds

The operator: negative regulaory site bound by the lac repressor protein

the lacZ, lacY and lacA genes to be transcribed for lactose metabolism

The ideal system would be where we can turn on and off the expression of a transgene without affecting the expression of other non-targetted genes. lacoperon is the best suited . here we can have a constitutive promoter along with the lac operator and the lacZ gene with the GFP gene.

using lactose the operon can be turned on, while the absence of lactose would render the expression of GFP off.

Therfore the system would have a GFP core promoter having lac operator region in between along with the GFP cDNA and the lacZ gene to metabolise the lactose . When lactose is in the system, the cAMP levels would increase the RNA polymerase binding, the operator would regulate the on /off switch and the further transcription of GFP and lacZ genes.

addition of glucose would turn the system off as the operator would be repressed.

another way to constitutively express GFP would be to use IPTG, as it is not metabolised by E.coli, the system would always be turned on.