Promotor Gene Mutation

[GomerPyle]

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If you mutate a promoter region of the DNA, does that ALWAYS turn a gene off or could there be instances where the DNA gets turned on?

Does the same apply to enhancer/silencer mutations?

 

[Jabbed]

Theoretically, it could enhance transcription. As a matter of course, it's considered more likely to be maladaptive.

Apply the same principle to qualitative enzymatic defects. It's theoretically possible that it'll enhance the enzyme's activity, but realistically it just ends up inhibiting it.

But for every rule of thumb, there's this.

 

[Transposony]

If you mutate a promoter region of the DNA, does that ALWAYS turn a gene off or could there be instances where the DNA gets turned on?

Does the same apply to enhancer/silencer mutations?

I don't see how promoter region mutation can cause gain of function since DNA polymerase will have difficulty recognizing the sequence either way.

However, it could be either way with enhancer/silencer mutations since they are acting via transcription unit which will still transcribe at the basal level even if it's enhancer/silencer is mutated.