How does mRNA stability influence gene expression?

How does mRNA stability influence gene expression?

• A. Degradation rates do not affect mRNA levels.
• B. Stability only affects translation, not mRNA levels.
• C. AU-rich elements do not influence stability.
• D. Degradation rates determine steady-state mRNA levels; AU-rich elements and miRNA modulate stability.

Answer: (D)

mRNA stability controls gene expression because how long an mRNA remains in the cell directly sets how much protein can be produced from it. The steady-state amount of mRNA results from the balance between how fast it is made and how fast it is degraded. If decay is rapid, mRNA levels stay low; if decay is slow, transcripts accumulate and more protein can be made. AU-rich elements in the 3' untranslated region are classic signals that recruit decay machinery, shortening the transcript’s half-life and lowering its abundance. MicroRNAs can bind complementary sites and promote deadenylation and decay or repress translation, both of which alter stability and, consequently, mRNA levels. So degradation rates determine steady-state mRNA levels, and AU-rich elements and miRNAs modulate stability to fine-tune gene expression.

mRNA stability controls gene expression because how long an mRNA remains in the cell directly sets how much protein can be produced from it. The steady-state amount of mRNA results from the balance between how fast it is made and how fast it is degraded. If decay is rapid, mRNA levels stay low; if decay is slow, transcripts accumulate and more protein can be made.

AU-rich elements in the 3' untranslated region are classic signals that recruit decay machinery, shortening the transcript’s half-life and lowering its abundance. MicroRNAs can bind complementary sites and promote deadenylation and decay or repress translation, both of which alter stability and, consequently, mRNA levels.

So degradation rates determine steady-state mRNA levels, and AU-rich elements and miRNAs modulate stability to fine-tune gene expression.