Question

g A mutation occurs upstream of gene A in the region encoding the ribosome binding site, making it bind more weakly to the ribosome. Predict how this mutation will impact the levels of mRNA and protein produced for gene A. Clearly state how mRNA levels will change and how protein levels will change in this mutant relative to wild type bacteria. Restrict your answer to 1-2 sentences.

Answer 1

Answer:

it is expected that the mutation results in a reduced initiation of translation and thereby decreasing the level of the protein A, while it does not change the level of mRNA A

Explanation:

Translation in bacteria starts with the formation of the initiation complex which is composed of the small ribosomal subunit, the messenger RNA (mRNA), initiation factors and the initiator transference RNA (tRNA) containing N-formyl-methionine. The small ribosomal subunit binds to a polypurine stretch of variable length in the mRNA called 'the Shine-Dalgarno sequence'. A mutation in this sequence reduces the affinity of the ribosome for the mRNA, thereby, in this case, decreasing the level of protein A. Since transcription occurs before translation, it is expected that this mutation does not change the level of expression of the mRNA A.