Question

A normal mRNA that reads 5’ – UGCCAUGGUAAUAACACAUGAGGCCUGAAC– 3’ has an insertion mutation that changes the sequence to 5’ -UGCCAUGGUUAAUAACACAUGAGGCCUGAAC– 3’. Translate the original mRNA and the mutated mRNA, and explain how insertion mutations can have dramatic effects on proteins. (Hint: Be sure to find the initiation site.)

Short answer

Met – Val – Ile – Thr – His – Glu – Ala (Original mRNA translation)

Met – Val – Asn – Asn – Thr (mutated mRNA translation)

Step-by-step solution

Step 1. Introduction

The translation is a process of protein synthesis in which information encoded in mRNA is directs the addition of amino acids during protein synthesis.

Step 2. Explanation

Original mRNA reads 5’ – UGCCAUGGUAAUAACACAUGAGGCCUGAAC– 3’

It is translated to form Met – Val – Ile – Thr – His – Glu – Ala;

While mutated mRNA reads 5’ -UGCCAUGGUUAAUAACACAUGAGGCCUGAAC– 3’

It is translated to form Met – Val – Asn – Asn – Thr;

Insertion of the nucleotide can have a dramatic effect as it shifts the frame for codon which alters the amino acids encoded by the mRNA, as a result, it led to the addition of premature stop or start sites.