RNA-induced silencing complex (RISC)

Definition

RNA-induced silencing complex (RISC) is a multi-protein complex that mediates gene silencing through RNA interference (RNAi). It incorporates small RNA molecules, such as siRNA or miRNA, to degrade target mRNA.

5 Must Know Facts For Your Next Test

1. RISC plays a crucial role in post-transcriptional gene regulation by degrading specific mRNAs.
2. It is composed of multiple proteins, including Argonaute, which is essential for its function.
3. RISC becomes activated upon binding with small interfering RNAs (siRNAs) or microRNAs (miRNAs).
4. The process of mRNA degradation by RISC leads to decreased protein synthesis, thereby regulating gene expression.
5. The formation of RISC is a key step in the RNA interference pathway and is essential for cellular defense mechanisms against viruses.

Review Questions

• What are the main components of the RNA-induced silencing complex (RISC)?
• How does RISC contribute to the regulation of gene expression?
• Which types of RNA molecules are involved in activating RISC?

Related terms

siRNA: Small interfering RNA that guides RISC to its target mRNA for degradation

miRNA: MicroRNA that also guides RISC but generally causes translational repression rather than direct degradation

Argonaute protein: A critical component of the RISC responsible for binding small RNAs and facilitating mRNA cleavage