Question

A 4-base deletion in the AAUAAA sequence in the 3' untranslated region of an mRNA that eliminates the AAU, thereby preventing RNA Polymerase from polyadenylating the mRNA, would have the effect of:

Answer 1

Answer:

decreasing the number of copies of the polypeptide translated from this mRNA

Explanation:

Polyadenylation refers to the addition of multiple adenosine monophosphates (i.e., a polyA tail) to an RNA molecule, usually a messenger RNA (mRNA). Polyadenylation is catalyzed by an RNA polymerase called poly(A) polymerase (PAP), which adds adenine nucleotides to the mRNA. In eukaryotic cells, polyadenylation is required to produce a mature mRNA which is then used as template for protein synthesis during translation. This posttranscriptional modification (polyadenylation) is known to stabilize the mRNA by preventing its degradation by exoribonucleases, i.e., enzymes that degrade RNA molecules by removing terminal nucleotides from 3' and 5' ends. In consequence, it is expected that a mutation that prevents polyadenylation of a target mRNA decrease the number of copies of the protein translated from this mRNA.