Forum: Genes inhibiting each other's expression
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gravatar for priya.bmg
5 months ago by
priya.bmg0
priya.bmg0 wrote:

Hi,

Can two genes repress each other's expression?. For example, Gene A inhibits Gene B, Gene B inhibits Gene A. Gene A is a transcription factor goes and binds to the promoter of Gene B and inhibits Gene B expression. Similarly, gene B is a transcription factor, inhibits Gene A expression. So, both Gene A and Gene B are not expressed. Is this mechanism biologically plausible?

Thanks

gene expression forum • 218 views
ADD COMMENTlink modified 5 months ago by i.sudbery11k • written 5 months ago by priya.bmg0
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gravatar for i.sudbery
5 months ago by
i.sudbery11k
Sheffield, UK
i.sudbery11k wrote:

Yes. This is called a double negative feedback loop. In situations where the inhibition is cooperative (that is, for a doubling in the level of one gene, the level of the other gene more than halves), this circuit forms a bi-stable switch. In a bistable system, only one of the genes can be expressed at once, and which one it is depends on the history of the system (technically, the system has a hysteresis).

Interesting, given how useful they are, such circuits are unrepresented in transcription regulatory networks.

ADD COMMENTlink written 5 months ago by i.sudbery11k

Underrepresented in the networks people have inferred or constructed. Hidden phenomena are hidden.

ADD REPLYlink written 5 months ago by karl.stamm3.9k

Perhaps, but their might be other reasons. The requirement for a really good hill coefficient on the repression to properly function as a bistable swtich is difficult to evolve, and without that, you just kind of get an averaging of the expression of the two. However, double negative feedback is over-represented when we talk about a TF and miRNA. One can show that this is because miRNA regulation is inherently non-linear, and so the cooperativity is built in, and thus easier to evolve.

ADD REPLYlink written 5 months ago by i.sudbery11k

Thank you for the explanation

ADD REPLYlink written 5 months ago by priya.bmg0
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