Question

A scientist modified the structure of a promoter region of a gene. What could be its effect on transcription and translation?

Answer 1

The gene could be downregulated

Answer 2

RNA polymerase can't bind on the promoter region, so no transcription takes place, consequently, no protein translation.

Answer 3

I mean, if you modify the structure of a promoter in an aleatory way, probably it will not work anymore. Then it will stopes to promoting the transcription of that gene, and that gene will not be transcripted anymore.

Answer 4

There are two variables at work here: the first is whether the change in the promoter increases or decreases its affinity for the transcription factor. Most changes cause a decrease in binding affinity but not all.

The second is whether the transcription factor up regulates or down regulates transcription. That cuts both ways as well.

Increasing the promoter's affinity for its transcription factor will lead to more transcription if the transcription is an up-regulator and less transcription if it is a down regulator. And decreasing the promoter's affinity for it's transcription factor will lead to more transcription if it is a down regulator and less transcription if it is an up regulator.

Prob not as straight forward as it first appeared.

Answer 5

blues, he is talking about "the promoter"; that includes the "core promoter (tatabox), proximal promoter and distal promoter". You are just talking about the proximal or distal promoter zones. Them have secuences for regulatory transcription factors, and then could enhance or silence. But "the promoter" includes the most importante sequence that is the CORE promoter. In tata box genes, the "tata box" is the most fundamental part of the promoter. If you get that part mutated, then you only may have no transcription of that gene. .

Answer 6

The problem here is only the "definitions" that we use. In cell papers and for example in "alberts", talking with property, they distinguish between "basal transcription factors" and "regulatory transcription factors". The first ones bind at the tatabox site, and are fundamental to the PIC formation. The regulatory ones can bind at regulatory sites to regulate or downregulate. The problem is that speaking lightly we use to say "transcription factors" when we are rigorously talking about regulatory transcription factors. And that is a problem of the jargom.

Answer 7

You are absolutely right about the distinction between the core transcriptional machinery and binding sites and the regulatory transcriptional machinery and its binding sites.

But the question does not distinguish between them. It just says "promoter region." I take that to include, if not exactly mean, the regulatory elements as well as the TATA box and other core elements.

Answer 8

Oh, yes, you were perfectly right too.