You are studying the translation of mRNAs derived from human erythrocytes in cell-free system derived from the E coli bacterium. You find the human globin mRNA is translated with extremely low efficiency in this system. Which of the following is the best explanation for these findings?

Question

Quizplus · Accepted Answer

The Shine-Dalgarno sequence is a ribosomal binding site in bacterial mRNA, which is necessary for initiating translation in prokaryotes like E. coli. Human mRNA lacks this sequence, leading to low translation efficiency in a bacterial system. Initiation of translation in both prokaryotes and eukaryotes requires a specific initiator tRNA and the recognition of an AUG codon in the mRNA. In the polycistronic prokaryotic RNAs this AUG codon is located adjacent to a Shine-Delgarno element in the mRNA. The Shine-Delgarno element is recognized by complimentary sequences in the small subunit rRNA. The lack of the Shine-Delgarno sequence in the globin RNA would restrict its translatability, as evidenced by the low efficiency of translation in the E Coli-derived system.

You Are Studying the Translation of MRNAs Derived from Human