After a successful over-expression of a key enzyme in a target pathway, Surprisingly, we have been noticed that another key Enzyme that leads our target pathway into a non-target-branch has been downregulated according to the Real-Time result. we wonder why? Does anyone have any idea?
Sincerely, I'm looking forward
Genes could be related, especially if they contribute to the same product. (By increasing and decreasing you obtain the same balanced product)
Tnx for ur answer. These two enzymes (A and B) are using the same substrate. these two enzymes are competing to use this substrate, we over-express the enzyme 'A' to lead the pathway into our goal metabolic, and we succeed it. But according to the Real-time result, we notice the high downregulation of enzyme 'B', We wonder, How and Why enzyme B has been affected.
I have several theories.
Apparently the enzymes regulate the product by reducing, but the downregulation means there is enough product, the enzyme then sets back as there is enough product. If not, the enzyme would be active, but they act on the same product. The enzyme then wants the product. Avoid the lack of build up. Maybe sending the product somewhere. (Like a toxin or venom?) I pull the product and if not I send it somewhere. Maybe if I know more of downregulation.?...
It would be a possibility that the final product derived from the target pathway is the major product required in the cellular processes .Hence via positive feedback regulation it might be increasing its synthesis from the target pathway and restricting or avoiding synthesis of products(non -target branch) not required by the cell.
Ria Khare and Mª Angeles Zorrilla Lopez-Perea I really appreciate your answers, I think with a picture that I uploaded below it will be easier to declare my question.
My project was about Metabolic engineering by the overexpression of the A enzyme in order to improve the final goal product, in the blue_color box in the picture, and this goal has been successfully done. Now according to the Real-Time results, we saw The B Enzyme had been 6 percent downregulate comparing with the control experiment. consider the B Benzyme was 1 in the Treatment and 6 in the control. The question is Why and How Enzyme B has been low expressed in treatment? We only change the expression of the
A enzyme.
(If both enzymes have the same objective, maybe they are uneccesary), as one is below the other. I act on the product, (both) if not the enzyme stays back. I wqnt two enzymes for rhe same final route but stays downregulated as the large increase in this product is present.
(I constitutively express the product, but the enzyme works better and as I have rhe same or more amount of product I stay back. But only as one increases). I would like to know if it is a question on level. (Reaching a particular level I obtain a result.
Sorry I'm not offering the answer straight away.
I will take a look afterwards
(maybe enzyme b is inhibited by the product.
maybe enzyme A is upregulated by lack of product or at least product b)
maybe genetically and not at the products.
trying to remove the substrate and is why I'm turning it to A. I don't wqnt to remove as much, as enzyme A is doing the work. b is not necesqry or at least in a second plane compared to A. is enzyme A quicker or more efficie nt?
Mª Angeles Zorrilla Lopez-Perea Both enzymes are equally necessary for the organism, Enzyme A leads to product A, and Enzyme B leads to product B, as it clears in the above picture, and both products are necessary for the organism. we wanted to increase product A and we achieve it by overexpression of Enzyme A. Now, wonder, why Enzyme B has been highly low expressed? and How?. Maybe product A inhibits the expression of enzyme B, but why? and how? Maybe there are other reasons...
maybe product b is an inhibitor of enzyme a. allosteric inhibition.
(maybe some kind of protection for mutation?).
b is not made when there is enough of a (or b is made when there is not enough of a).
it is true you might not get one answer at a time
Thank you, very much dear Mª Angeles Zorrilla Lopez-Perea. Well, I'm looking
forward to gathering more information.
Plants react to stress conditions by alteration of gene expression that leads to the up-regulation and down-regulation in the synthesis of enzymes. Stressors trigger the expression of a large number of genes and, thereby, several novel proteins are synthesized which have potential roles in conferring stress tolerance. So, non-target enzyme has been downregulated while a target gene has been successfully overexpressed because of the regulatory genes (encode various transcription factors (TFs), which can regulate various stress-responsive genes cooperatively and/or separately and, thus, constitute a gene network) and the functional genes (encode metabolic compounds such as, amines, alcohols, and sugars, play a crucial role in metal stress tolerance).
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