RNA silencing (RNAi):
- It is a process that occurs in all eukaryotic cells as an approach to cellular defense.
- It acts as an antiviral mechanism in higher plants and insects.
Process:
- RNA silencing mechanism involves the initial processing of inducing dsDNA into small interfering RNA (siRNA).
- These siRNAs are 20-25 nucleotides long corresponding to both sense and anti-sense strands of the target gene.
- These siRNAs correspond to a protein complex referred to as RNA-induced silencing complex (RISC).
- It acts as a guide to select target RNAs and process their degradation.
- In plants, silencing is majorly achieved by methylation within transcribed region of the gene corresponding to the target RNA.
Practical applications of RNA silencing:
- Biomedicine: medicines have been developed for ocular and retinal disorders, cancer, kidney disorders, etc, using this technique.
- Nematode-resistant plant: in the tobacco plant, root infestation by Meloidogyne incognita has been eradicated using RNA silencing.