Explain how the use of alternative promoters and alterna...

Question

Explain how the use of alternative promoters and alternative polyadenylation signals produces mRNAs with different 5' and 3' ends.

Accepted Answer

Hi everyone here's our next problem. The usage of alternative poly A sites in eukaryotic gene expression and then we have different endings to the sentence. Choice A says allows a single gene to encode multiple RNA transcripts. Choice be the mature five prime end cap of eukaryotic M. RNA uses alternative policy. A sites choice is both A and B. And choice D. Is none of the above. So we basically just need to evaluate choices A and B. To see what our answer is. Choice A says allows a single gene to encode encode multiple RNA transcripts. Well this is correct kind of in two different ways. Um the poly A tail, we now know it can be synthesized in different places on the same gene. If it occurs in an internal in tron or Exxon it will actually change the coding of the protein. So change the protein that's coded for. So that's one way it can change this. Otherwise it can just alter The three prime untranslated region of the M. RNA transcript. And this means the same protein is produced but it can alter the activity of it or the regulation of it. The fate of the M. R. N. A. Because it has different availability of binding sites for binding proteins and um M. I. R. N. A. That might alter the fate of that M. R. N. A. So kind of by these two different mechanisms it allows a single gene to encode multiple M. RNA transcripts. So this is a correct statement. So we know that then choice D. None of the above must not be our answer. So let's move onto Choice B. B says the mature five prime end cap of eukaryotic M. RNA is alternative poly A sites. Well, this would be incorrect because the poly A tail Is added to the three prime end of the M. R. N. A. The five prime cap is that is synthesized the very beginning of transcription and helps to stabilize the M. RNA transcript, preventing it from decay. So this is choice B is incorrect, not our answer choice. Therefore, choice. See both A and B must also not be our answer. So that leaves are correct answer as choice A. So the usage of alternative policy sites and you carried a gene expression. Choice A allows a single gene to encode encode multiple M. RNA transcripts. See you in the next video.

Explain how the use of alternative promoters and alternative polyadenylation signals produces mRNAs with different 5' and 3' ends.

Key Concepts

Alternative Promoters

Alternative Polyadenylation

mRNA Isoforms

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