RNA interference

Definition

RNA interference (RNAi) is a biological process in which small RNA molecules inhibit gene expression or translation by targeting specific mRNA molecules for degradation or preventing their translation. This process is crucial for regulating gene expression in various cellular processes and maintaining cellular homeostasis, thus playing a significant role in the control of gene expression in both normal and disease states.

5 Must Know Facts For Your Next Test

1. RNA interference was first discovered in plants, but it is now known to occur in many organisms, including animals and fungi.
2. The RNAi mechanism is initiated when long double-stranded RNA is cleaved into smaller fragments by the enzyme Dicer.
3. Once formed, siRNAs or miRNAs associate with the RNA-induced silencing complex (RISC), which carries out the degradation or inhibition of target mRNA.
4. RNA interference has been harnessed as a powerful tool for gene silencing in research and therapeutic applications, including cancer treatment and viral infections.
5. In addition to regulating gene expression, RNA interference also plays a key role in protecting organisms from viral infections by targeting viral RNA for degradation.

Review Questions

• How does RNA interference contribute to the regulation of gene expression at the molecular level?
  • RNA interference contributes to the regulation of gene expression by utilizing small RNA molecules like siRNAs and miRNAs to bind to specific mRNAs. This binding leads to either the degradation of the mRNA or inhibition of its translation. By selectively silencing specific genes, RNAi allows cells to fine-tune protein production according to their needs, which is essential for various cellular functions and responses.
• What roles do Dicer and RISC play in the RNA interference process, and why are they important for gene regulation?
  • Dicer is crucial for processing long double-stranded RNA into small RNA fragments that are necessary for initiating RNA interference. After Dicer cuts the RNA, these small fragments are loaded onto the RNA-induced silencing complex (RISC). RISC then uses these small RNAs to recognize and bind to complementary mRNA sequences, leading to either mRNA degradation or translational repression. The collaboration between Dicer and RISC is fundamental for ensuring that gene regulation through RNAi occurs efficiently and accurately.
• Evaluate the potential therapeutic applications of RNA interference technology and discuss any challenges associated with its use.
  • RNA interference technology holds significant promise for therapeutic applications, particularly in targeting diseases such as cancer and viral infections by silencing specific genes involved in disease progression. However, challenges remain, including the delivery of small RNA molecules to target cells effectively and avoiding off-target effects that could lead to unintended consequences. Additionally, ensuring stable expression and long-lasting effects while minimizing immune responses poses hurdles that researchers must overcome before widespread clinical implementation can occur.

Related terms

Small interfering RNA (siRNA): Short, double-stranded RNA molecules that are part of the RNAi mechanism and are involved in the degradation of target mRNA.

MicroRNA (miRNA): Small, single-stranded RNA molecules that also play a role in gene regulation by binding to complementary sequences on target mRNAs, leading to their repression or degradation.

Dicer: An enzyme that processes long double-stranded RNA into small interfering RNAs and microRNAs, initiating the RNA interference pathway.