Dicer

Dicer is a type of enzyme that plays a crucial role in the RNA interference pathway, where it cleaves long double-stranded RNA molecules into short double-stranded fragments of approximately 20-25 base pairs. Dicer facilitates the production of small interfering RNA (siRNA) and microRNA (miRNA), which are involved in gene silencing and post-transcriptional regulation of gene expression.

Function

Dicer is a part of the ribonuclease III family of enzymes. It recognizes and binds to double-stranded RNA (dsRNA) and cleaves it into short double-stranded fragments. These fragments, known as siRNA and miRNA, are then incorporated into the RNA-induced silencing complex (RISC), which targets and degrades complementary RNA molecules, thereby preventing their translation into protein.

Structure

Dicer contains several functional domains, including a helicase domain, a PAZ domain, two RNase III domains, and a dsRNA-binding domain. The helicase domain is involved in unwinding the dsRNA, the PAZ domain binds to the end of the dsRNA, and the RNase III domains cleave the dsRNA at specific sites.

Role in Disease

Alterations in the function of Dicer have been implicated in various diseases. For example, mutations in Dicer have been associated with cancer, autoimmune diseases, and neurodegenerative diseases. In cancer, reduced expression of Dicer has been linked to poor prognosis.

See Also

• RNA interference
• MicroRNA
• Small interfering RNA
• Gene silencing
• Gene expression

References

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  Dicer domain structure
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  Simplified RNA interference pathway
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  MicroRNA biogenesis