RNA interference

Definition

RNA interference (RNAi) is a biological process in which small RNA molecules inhibit gene expression or translation by neutralizing targeted mRNA molecules. This mechanism plays a critical role in regulating gene expression, providing a means for cells to control the levels of proteins produced from specific genes and defend against viral infections. By targeting specific mRNA sequences, RNAi can effectively silence genes, making it an essential tool for understanding gene function and regulation.

5 Must Know Facts For Your Next Test

1. RNA interference was first discovered in plants as a mechanism for post-transcriptional regulation of gene expression and later found in animals and fungi.
2. The process of RNA interference involves the incorporation of siRNA or miRNA into the RNA-induced silencing complex (RISC), which then mediates the degradation or inhibition of target mRNAs.
3. RNAi can be used as a powerful research tool to study gene function by selectively silencing genes of interest in various organisms.
4. In addition to its role in regulating normal cellular processes, RNA interference is also involved in the defense against viral infections by targeting viral mRNA for degradation.
5. Therapeutically, RNA interference has potential applications in treating diseases by targeting and silencing disease-causing genes, although challenges remain in delivering RNAi therapeutics effectively.

Review Questions

• How does RNA interference contribute to the regulation of gene expression within a cell?
  • RNA interference regulates gene expression by using small RNA molecules like siRNA and miRNA to bind to complementary mRNA sequences. This binding leads to the degradation of the target mRNA or inhibition of its translation into protein. By selectively silencing specific genes, RNAi allows cells to finely tune protein production, respond to environmental changes, and maintain homeostasis.
• Discuss the roles of siRNA and miRNA in the RNA interference process and their differences.
  • Both siRNA and miRNA play vital roles in the RNA interference process but differ in their origins and mechanisms. siRNA is usually derived from long double-stranded RNA and primarily targets specific mRNAs for degradation through RISC. In contrast, miRNA is processed from single-stranded precursor molecules and can regulate multiple mRNAs by binding imperfectly to their target sites, often leading to translational repression rather than complete degradation. This distinction highlights their different strategies for modulating gene expression.
• Evaluate the potential therapeutic applications of RNA interference in treating genetic diseases and discuss the challenges that accompany its use.
  • The therapeutic applications of RNA interference are promising, particularly for targeting genes involved in genetic diseases such as cancer and viral infections. By designing specific siRNAs to silence disease-causing genes, researchers aim to reduce the production of harmful proteins. However, challenges include ensuring efficient delivery of RNAi agents to target tissues, avoiding off-target effects, and managing immune responses that could arise from introducing foreign RNA molecules into the body. Overcoming these hurdles is essential for realizing the full potential of RNAi-based therapies.

Related terms

siRNA: Small interfering RNA (siRNA) are short, double-stranded RNA molecules that play a key role in the RNA interference pathway by guiding the silencing of specific mRNA targets.

miRNA: MicroRNA (miRNA) are small, non-coding RNA molecules that also regulate gene expression by binding to complementary sequences on target mRNAs, leading to their degradation or inhibition of translation.

Dicer: Dicer is an enzyme that processes long double-stranded RNA and precursor microRNA into functional siRNA and miRNA, which are crucial for the initiation of RNA interference.