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the figure below shows the results of an experiment to determine the role of the

ID: 212241 • Letter: T

Question


the figure below shows the results of an experiment to determine the role of the 5' and 3' tail in mRNA translation efficiency. Based on the graphs and the table below, explain how the 5' cap and 3' tail regulate translation efficiency and MENA half-life

The figure below shows the results of an experiment to determine the role of the 5' cap and translation efficiency. Based on the graphs and the table below, explain how the 5' cap and 3' tail regulate translation efficiency and mRNA half-life. (8 points) 2 4. E tciency LUC A so Luc 92 3.7 o 9e Luc Ao 88 92 Capped LUC A Se LuC Luc 2160 LUC 1.9 0 100 15 003 200 250 300LuC A32100 Mnutes

Explanation / Answer

Answer:

The translational efficiency of uncapped, poly(A) + Luc mRNA was equivalent to that of the uncapped, poly(A)- mRNA. In contrast, the addition of a poly(A) tail to capped Luc mRNA increased translational efficiency 15-fold, demonstrating that the poly(A) tail not only regulates translational efficiency but requires a cap for function.

In this experiment, cap function was stimulated by a poly(A) tail. Although capped, poly(A)- Luc mRNA was translated 23-fold more efficiently than the uncapped form; the translational efficiency of the poly(A) + Luc mRNA was 365- fold greater for the capped versus the uncapped form .

The functional half-life of the uncapped poly(A) + Luc mRNA was 3.7-fold longer than the corresponding poly(A)- mRNA. Increased message stability should not affect the rate of translation but will directly affect the final level of protein produced.

The functional half-life for the capped, poly(A) + mRNA was 1.9-fold greater than for the corresponding poly(A)- mRNA.