Definition
RNA-induced silencing complex, or RISC, is a multiprotein complex that incorporates one strand of a small interfering RNA (siRNA) or micro RNA (miRNA). RISC uses the siRNA or miRNA as a template for recognizing complementary mRNA. When it finds a complementary strand, it activates RNase and cleaves the RNA. This process is important both in gene regulation by microRNAs and in defense against viral infections, which often use double-stranded RNA as an infectious vector.
Characteristics
The RNA endonuclease Dicer plays a role in aiding RISC action by providing the initial RNA material to activate the complex as well as the first RNA substrate molecule. When the Dicer cleaves a pre-miRNA stem-loop or a dsRNA, a 20- to 25-base-pair double-stranded RNA fragment is formed with a two-nucleotide 3′ overhang at each end. One strand is integrated into the RISC complex. This strand is known as the guide strand and is selected by the argonaute protein, the catalytically active RNase in...
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References
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Zhang, Y. (2013). RNA-induced Silencing Complex (RISC). In: Dubitzky, W., Wolkenhauer, O., Cho, KH., Yokota, H. (eds) Encyclopedia of Systems Biology. Springer, New York, NY. https://doi.org/10.1007/978-1-4419-9863-7_329
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DOI: https://doi.org/10.1007/978-1-4419-9863-7_329
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