View source for RNA Interference in Gene Silencing

==Introduction==
RNA interference (RNAi) is a biological process in which RNA molecules inhibit gene expression or translation, by neutralizing targeted mRNA molecules. The process is used by many different organisms to regulate the activity of genes. RNAi is also known as post-transcriptional gene silencing (PTGS) and quelling. The RNAi pathway is initiated by the enzyme Dicer, which cleaves long double-stranded RNA (dsRNA) molecules into short fragments of 20 nucleotides. These small fragments, known as small interfering RNAs (siRNAs), are then incorporated into the RNA-induced silencing complex (RISC). The siRNA strands guide the RISC to the mRNA that matches their sequence. The RISC then cleaves the mRNA, thereby preventing it from being used as a translation template.

[[Image:Detail-39717.jpg|thumb|center|A microscopic view of RNA molecules interacting with each other and with other cellular components.|class=only_on_mobile]]
[[Image:Detail-39718.jpg|thumb|center|A microscopic view of RNA molecules interacting with each other and with other cellular components.|class=only_on_desktop]]

==Mechanism of RNA Interference==
RNA interference involves the introduction of double-stranded RNA (dsRNA) into a cell or organism. The dsRNA is processed by Dicer, an RNase III family endonuclease, into small interfering RNAs (siRNAs) of approximately 21-23 nucleotides in length. The siRNAs are then incorporated into the RNA-induced silencing complex (RISC), which uses the siRNA as a template for recognizing complementary mRNA. Once the RISC-siRNA complex binds to the target mRNA, the mRNA is cleaved and subsequently degraded, preventing it from being used as a template for protein synthesis.

==Role in Gene Silencing==
RNA interference is a key mechanism of gene silencing in many organisms, including humans. It plays a crucial role in defending against viral infections, controlling transposon activity, and regulating gene expression. In the context of gene silencing, RNAi can be used to selectively turn off or "knock down" specific genes. This is achieved by introducing siRNAs that are complementary to the mRNA of the target gene. The siRNAs guide the RISC to the target mRNA, leading to its degradation and thus preventing the production of the protein encoded by the gene.

==Applications of RNA Interference==
RNA interference has been harnessed for various applications in biotechnology and medicine. In research, RNAi is used to study the function of genes by observing the effects of silencing them. In medicine, RNAi has potential for treating diseases by silencing harmful genes. For example, RNAi-based therapies are being developed for treating viral infections, cancer, and genetic disorders. However, the delivery of siRNAs into cells and the specificity of their action remain significant challenges for the therapeutic use of RNAi.

==See Also==
* [[Gene Expression|Gene expression]]
* [[Gene Silencing|Gene silencing]]
* [[Dicer|Dicer]]
* [[RISC|RISC]]
* [[siRNA|siRNA]]

[[Category:Genetics]]
[[Category:Molecular Biology]]
[[Category:Biotechnology]]
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